ci: re-run make check on every cibuild instead of serving it from the layer cache (closes #115 )

`script/cibuild` was plain `docker build .`. The Dockerfile does `COPY . .` and then `RUN make check`, and Docker invalidates `COPY . .` only on a content change, so on a byte-identical tree the check layer was reused and the suite never ran. The script's header comment claimed that a successful build implies all checks pass, which was false whenever the cache was warm. Reproduced on this branch's parent: a second consecutive run returned success in 283 ms with `#13 [builder 9/10] RUN make check` reported `CACHED`. That matters more here than in a typical repo. DNS is never mocked in this repository, so the suite queries live DNS and its outcome varies with real-world conditions; caching the verdict of a non-deterministic check replays a stale result in exactly the case where re-running is most valuable. It is also the gate every PR is verified through. Fix: declare `ARG CHECK_EPOCH` immediately above the check step and expand it into the command, with `script/cibuild` passing a fresh `$(date +%s%N)` per invocation. A build argument's value participates in the cache key of later instructions in the stage even when they do not reference it, so a fresh value busts this layer either way; the value is expanded into the command deliberately, which makes the invalidation a property of the command string itself rather than of how a given builder treats unreferenced args, and surfaces the epoch in the build log as a diagnostic. Placing the ARG here and no earlier keeps the pinned toolchain installs and `go mod download` above the invalidation line, so only the check and the steps after it re-run. The epoch is nanosecond granular so that two concurrent invocations starting in the same second cannot share a value. A plain `docker build` without the argument caches as before; nothing outside the CI entrypoint changes behaviour. Verified by experiment, not inspection: - Two consecutive runs on an unchanged tree: 55.2 s and 42.2 s, both exit 0, with distinct epochs. The second run shows `RUN echo "check epoch: ..." && make check` executing for 36.0 s and 216 passing tests across all eight packages, while `apk add`, both pinned `go install` steps, `go mod download`, `COPY go.mod go.sum` and `COPY . .` all report `CACHED`. - Negative control: planted `internal/config/zz_negative_control_test.go` calling `t.Fatal("NEGATIVE-CONTROL-115: planted failure, cache did not serve this layer")`. The build failed in 24.7 s with exit 1, printing that exact message and `--- FAIL: TestNegativeControlIssue115`, and the check step exited with code 2. A cached layer cannot produce a failure predicted in advance, so this establishes the suite ran. The file was then removed, `git status` confirmed clean, and the tree built green again in 48.1 s. - Total build time 42-55 s against the policy's 5-minute ceiling. - `make check` green. No pin touched: the `golang` and `alpine` sha256 digests, golangci-lint `c0d3ddc9`, and goimports `009367f5` are unchanged, and `.golangci.yml` still hashes to `021cc83f4e6f...`.
2026-08-09 06:22:28 +00:00
82 changed files with 1765 additions and 9617 deletions
@@ -1,9 +1,6 @@
-# .git is sent, without its config: the builder stage derives the version it
+.git/
 # stamps into the binary from it, and `git describe` does not need the config,
 # which can hold a credential (a password in the remote URL, a CI token). No
 # tracked file may be listed here: git in the build would see it as deleted
 # and mark the version -dirty, and an excluded .md would silently drop out of
 # the prettier check in Dockerfile.fmt.
 .git/config
 bin/
-node_modules/
+*.md
 LICENSE
 .editorconfig
 .gitignore
@@ -1,17 +1,9 @@
 name: check
 on: [push]
 # A new push to a branch cancels that branch's older run, queued or running;
 # runs on other branches, `next` and `main` among them, are left alone.
 concurrency:
    group: ${{ github.workflow }}-${{ github.ref }}
    cancel-in-progress: true
 jobs:
    check:
        runs-on: ubuntu-latest
        steps:
            # actions/checkout v4.2.2, 2026-02-28
            - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
              # script/cibuild needs no token, so none is left in .git/config.
              with:
                  persist-credentials: false
            - run: script/cibuild
@@ -1,5 +1,4 @@
 bin/
 node_modules/
 vendor/
 data/
 .env
@@ -10,20 +10,14 @@ run:
 linters:
  default: all
  enable:
    # Successor to the deprecated gomodguard. Named explicitly, rather than
    # left to `default: all`, because it carries the module policy below.
    - gomodguard_v2
  disable:
    # Genuinely incompatible with project patterns
    - exhaustruct      # Requires all struct fields
    - depguard         # Dependency allow/block lists
    - godot            # Requires comments to end with periods
    - wsl              # Deprecated, replaced by wsl_v5
    - wrapcheck        # Too verbose for internal packages
    - varnamelen       # Short names like db, id are idiomatic Go
    # Deprecated: the warning is attached to the old name, so it is
    # silenced by disabling that name, not by enabling the successor.
    - wsl              # Deprecated, replaced by wsl_v5
    - gomodguard       # Deprecated, replaced by gomodguard_v2
  settings:
    lll:
      line-length: 88
@@ -34,68 +28,6 @@ linters:
      max-complexity: 15
    dupl:
      threshold: 100
    depguard:
      # Test-support code must not be compiled into the shipped binary. A
      # test-support package exists to hand a test privileges the program
      # itself must never have, so a file that is not a test must not import
      # one. Test files, and the files inside a package whose directory name
      # ends in `test`, are where that code belongs, and are exempt.
      #
      # The deny list below is the one part of this file a repository is
      # expected to extend, and the only part it may. depguard matches an
      # import path against a list of prefixes, so it cannot be told "any path
      # whose last segment ends in test"; a repository's own test-support
      # packages have to be named here one at a time, by full import path,
      # under a module path that differs from repository to repository. Add
      # them; change nothing else.
      rules:
        test-support:
          list-mode: lax
          files:
            - "$all"
            - "!$test"
            - "!**/*test/**"
          deny:
            - pkg: net/http/httptest
              desc: >-
                Test-support code belongs in test files and in packages whose
                directory name ends in test, not in the shipped binary.
            - pkg: sneak.berlin/go/dnswatcher/internal/livednstest
              desc: >-
                Live-DNS test support belongs in test files and in packages
                whose directory name ends in test, not in the shipped binary.
    # Only decisions already recorded in the Go package defaults are
    # listed here. Every entry matches the module path exactly.
    gomodguard_v2:
      blocked:
        - module: github.com/rs/zerolog
          recommendations:
            - log/slog
          reason: "Structured logging is stdlib log/slog."
        # One entry per pre-fork module path, because the later releases
        # are separate paths. A prefix match would be shorter but would
        # also reach github.com/go-redis/redismock, the test double for
        # the successor these entries recommend.
        - module: github.com/go-redis/redis
          recommendations:
            - github.com/redis/go-redis/v9
          reason: "Pre-fork module; use the maintained go-redis v9."
        - module: github.com/go-redis/redis/v7
          recommendations:
            - github.com/redis/go-redis/v9
          reason: "Pre-fork module; use the maintained go-redis v9."
        - module: github.com/go-redis/redis/v8
          recommendations:
            - github.com/redis/go-redis/v9
          reason: "Pre-fork module; use the maintained go-redis v9."
        - module: github.com/sergi/go-diff
          recommendations:
            - github.com/aymanbagabas/go-udiff
          reason: "No unified diff output; use go-udiff."
        - module: github.com/hexops/gotextdiff
          recommendations:
            - github.com/aymanbagabas/go-udiff
          reason: "Unmaintained fork; use go-udiff."
 issues:
  max-issues-per-linter: 0
@@ -1,5 +0,0 @@
 bin/
 data/
 node_modules/
 .claude/
 static/css/tailwind.min.css
@@ -1,4 +0,0 @@
 {
    "tabWidth": 4,
    "proseWrap": "always"
 }
@@ -1,36 +1,13 @@
 # Lint stage - fast feedback on lint issues, before the build starts.
 # The linter is invoked directly rather than through `make lint`: that
 # target shells out to `docker build -f Dockerfile.lint`, and there is
 # no docker daemon inside a docker build. For the same reason this stage
 # runs only the Go half of `make fmt-check`; script/cibuild runs the
 # markdown half after this build.
 # script/cibuild and script/docker name this stage in --no-cache-filter.
 # golangci/golangci-lint:v2.12.2 (Debian-based), 2026-08-10
 FROM golangci/golangci-lint:v2.12.2@sha256:5cceeef04e53efe1470638d4b4b4f5ceefd574955ab3941b2d9a68a8c9ad5240 AS lint
 WORKDIR /src
 COPY go.mod go.sum ./
 RUN go mod download
 COPY . .
 RUN script/fmt-check-go
 RUN golangci-lint run --config .golangci.yml ./...
 # Build stage
 # script/cibuild and script/docker name this stage in --no-cache-filter.
 # golang 1.25-alpine, 2026-02-28
 FROM golang@sha256:f6751d823c26342f9506c03797d2527668d095b0a15f1862cddb4d927a7a4ced AS builder
 RUN apk add --no-cache git make gcc musl-dev binutils-gold
-# A build context sent as a tar archive keeps its files' owners, and git
+# golangci-lint v2.12.2, 2026-08-07
-# refuses to read a checkout owned by another user. Trust this one
+RUN go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@c0d3ddc9cf3faa61a4e378e879ece580256d76e5
-# whoever owns it.
+# goimports v0.42.0
-RUN git config --system --add safe.directory /src
+RUN go install golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0
 # Force BuildKit to run the lint stage before proceeding
 COPY --from=lint /src/go.sum /dev/null
 WORKDIR /src
 COPY go.mod go.sum ./
@@ -38,61 +15,44 @@ RUN go mod download
 COPY . .
-# Run the tests - build fails if any test fails
+# Run all checks - build fails if any check fails.
-RUN make test
+#
-
+# CHECK_EPOCH is a cache-busting build argument. Without it, an
-# Version stamped into the binary: the VERSION build arg when one is
+# unchanged tree leaves this layer's cache key identical and Docker
-# given and not empty (script/docker passes one), otherwise what
+# serves the previous verdict instead of re-running the suite, so the
-# `git describe` says of the .git in the build context, so a plain
+# build reports a green it did not earn. A build argument's value
-# `docker build .` of a clone stamps its tag or short commit. The build
+# participates in the cache key of later instructions in the stage even
-# arg reaches make through the environment.
+# when they do not reference it, so a fresh value busts this layer
-ARG VERSION
+# either way. It is expanded into the command deliberately: that makes
-
+# the invalidation a property of the command string itself rather than
-# A context that carries .git, as a directory or as a file, must yield a
+# of how a given builder treats unreferenced args, and it surfaces the
-# real version: one that is empty, `dev` or `unknown` cannot be traced
+# epoch in the build log as a diagnostic.
-# back to a commit.
+#
-RUN version="$(make version)"; \
+# Placing the ARG here and nowhere earlier keeps everything above it
-    if [ -e .git ]; then \
+# (toolchain install, go mod download) cached, so only the check and the
-        case "$version" in \
+# steps after it re-run. script/cibuild passes a fresh value per run; a
-            "" | dev | unknown) \
+# plain `docker build` without it caches as before.
-                echo "version is \"$version\" although the build context carries .git" >&2; \
+ARG CHECK_EPOCH
-                exit 1 ;; \
+RUN echo "check epoch: ${CHECK_EPOCH}" && make check
        esac; \
    fi
 # Build the binary
 RUN make build
 # Runtime stage
 # alpine 3.21, 2026-02-28
 FROM alpine@sha256:c3f8e73fdb79deaebaa2037150150191b9dcbfba68b4a46d70103204c53f4709
-RUN apk add --no-cache ca-certificates tzdata su-exec
+RUN apk add --no-cache ca-certificates tzdata
-COPY --from=builder /src/bin/dnswatcher /usr/local/bin/dnswatcher
+WORKDIR /app
 COPY deploy/docker-entrypoint.sh /usr/local/bin/docker-entrypoint.sh
-# dnswatcher runs as this unprivileged user. The entrypoint creates the
+COPY --from=builder /src/bin/dnswatcher /app/dnswatcher
-# data directory and gives it to this user on every start.
+
-RUN addgroup -S -g 10001 dnswatcher \
+# Create data directory
-    && adduser -S -G dnswatcher -u 10001 dnswatcher
+RUN mkdir -p /var/lib/dnswatcher
 ENV DNSWATCHER_DATA_DIR=/var/lib/dnswatcher
 # Config loading also reads a `.env` file and a file named `dnswatcher`
 # (any config extension, or none) from the working directory. `/` holds
 # neither, so every setting comes from the environment. Do not make the
 # data directory, or the binary's directory, the working directory.
 WORKDIR /
 # No USER: the entrypoint must start as root to set up the data
 # directory; it then runs dnswatcher as the dnswatcher user.
 EXPOSE 8080
-# busybox wget (already in alpine) probes the health endpoint every 10
+ENTRYPOINT ["/app/dnswatcher"]
 # seconds, so the container is healthy well before upaas reads its health
 # 60 seconds after a deploy and fails the deploy unless it is healthy.
 HEALTHCHECK --interval=10s --timeout=5s --start-period=10s --retries=3 \
    CMD wget -q -O /dev/null "http://127.0.0.1:${PORT:-8080}/.well-known/healthcheck" || exit 1
 ENTRYPOINT ["/usr/local/bin/docker-entrypoint.sh"]
@@ -1,54 +0,0 @@
 # prettier over the markdown, in a container, so it is never installed
 # on the host. script/fmt-check-markdown builds the fmt-check stage;
 # script/fmt builds fmt-out and takes the formatted files back.
 # node:22-bookworm-slim, 2026-09-05
 FROM node:22-bookworm-slim@sha256:83f487e0a63425e5b4d146fb5e5be574bcbe1b7b843d3ebafdd95eaf7767a7e5 AS nodedeps
 # prettier lives outside /src so that a `COPY . .` of the repo cannot
 # overwrite it, and so that node_modules never appears in the tree
 # prettier is about to walk.
 WORKDIR /tools
 # package.json pins the version and yarn.lock pins the bytes:
 # --frozen-lockfile installs exactly the lockfile's resolution and fails
 # if package.json disagrees with it, so the tool cannot float between
 # runs. yarn is the one in the image above.
 COPY package.json yarn.lock ./
 RUN yarn install --frozen-lockfile --non-interactive --no-progress
 ENV PATH="/tools/node_modules/.bin:${PATH}"
 WORKDIR /src
 # Read-only markdown check. Must match $stage in
 # script/fmt-check-markdown.
 FROM nodedeps AS fmt-check
 COPY . .
 # --config, not discovery: a .prettierrc that failed to arrive would
 # otherwise leave prettier on its defaults, where proseWrap is "preserve"
 # and every wrap this check exists to enforce passes. Missing the file is
 # a hard error instead. --no-editorconfig so that .prettierrc alone sets
 # the style.
 RUN prettier --config .prettierrc --no-editorconfig --check "**/*.md"
 # Write path. Not a check: script/fmt builds this and takes the files.
 FROM nodedeps AS fmt
 COPY . .
 RUN prettier --config .prettierrc --no-editorconfig --write "**/*.md"
 # Only the markdown leaves, with its paths intact, so that the export
 # below cannot put anything else back over the caller's working tree.
 RUN mkdir -p /out && cd /src && \
    find . -name '*.md' -type f -exec cp --parents '{}' /out/ ';'
 # Export target: `docker build --target fmt-out --output type=local`
 # writes /out's tree into a directory on the client, which is how
 # script/fmt gets formatted markdown back without a bind mount.
 # Must match $stage in script/fmt.
 FROM scratch AS fmt-out
 COPY --from=fmt /out/ /
@@ -1,29 +0,0 @@
 # Lint-only image: used by script/lint. golangci-lint is never run on
 # the host — the repo is COPYed into the build context and the linter
 # runs as a build step, so a successful build IS a clean lint. This
 # also works where the docker daemon is remote and bind mounts are
 # impossible.
 #
 # `golangci-lint config verify` is deliberately NOT run here: it
 # fetches its JSON schema over a live, unpinned HTTPS call, which would
 # make linting network-dependent and defeat hash-pinning. The cost of
 # that: unknown top-level keys in .golangci.yml are silently ignored,
 # so a mistyped or wrong-schema key lints clean while applying nothing.
 #
 # golangci/golangci-lint:v2.12.2 (Debian-based), 2026-08-10
 FROM golangci/golangci-lint:v2.12.2@sha256:5cceeef04e53efe1470638d4b4b4f5ceefd574955ab3941b2d9a68a8c9ad5240 AS deps
 WORKDIR /src
 # Dependencies first, so this stage stays cached across lint runs.
 COPY go.mod go.sum ./
 RUN go mod download
 # Everything below is invalidated on every run by the
 # --no-cache-filter=lint that script/lint passes: caching is explicitly
 # waived for linting, and a cached build lints nothing.
 FROM deps AS lint
 COPY . .
 RUN golangci-lint run --config .golangci.yml ./...
@@ -1,21 +0,0 @@
 MIT License
 Copyright (c) 2026 sneak
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
@@ -1,13 +1,7 @@
-.PHONY: all bootstrap setup build version lint fmt fmt-check test check clean hooks docker
+.PHONY: all bootstrap setup build lint fmt fmt-check test check clean hooks docker
 BINARY := dnswatcher
-# VERSION given on the command line (`make build VERSION=...`) or in the
+VERSION := $(shell git describe --tags --always --dirty 2>/dev/null || echo "dev")
 # environment, which is how the Dockerfile's VERSION build arg arrives,
 # wins over what `git describe` says of this checkout. An empty one counts
 # as not given; `override` is what replaces an empty command-line value.
 ifeq ($(VERSION),)
 override VERSION := $(shell git describe --tags --always --dirty 2>/dev/null || echo "dev")
 endif
 LDFLAGS := -X main.Version=$(VERSION)
 # Standard targets are thin shims; the implementations live in script/
@@ -25,10 +19,6 @@ setup:
 build:
 	go build -ldflags "$(LDFLAGS)" -o bin/$(BINARY) ./cmd/dnswatcher
 # Prints the version `make build` stamps; the Dockerfile checks it.
 version:
 	@echo "$(VERSION)"
 test:
 	@script/test
@@ -1,6 +1,6 @@
 ---
 title: Repository Policies
-last_modified: 2026-08-07
+last_modified: 2026-07-06
 ---
 This document covers repository structure, tooling, and workflow standards. Code
@@ -189,13 +189,8 @@ style conventions are in separate documents:
  module under test to verify it compiles/parses. There is no excuse for
  `make test` to be a no-op.
- `make test` must complete in under 60 seconds. That is the hard cap, and a
+- `make test` must complete in under 20 seconds. Add a 30-second timeout in the
-  suite that exceeds it fails. Under 20 seconds is the target. A suite between
+  Makefile.
  20 and 60 seconds is still green, but the overage must be filed as an
  improvement bug against that repo. Add a 90-second timeout to the test
  invocation in the Makefile (`go test -timeout 90s`). The backstop deliberately
  sits above the hard cap so that it catches a genuinely hung test rather than a
  merely slow one.
 - **`make test` should use the conditional verbose rerun pattern.** Run tests
  without `-v` (verbose) first. If tests fail, automatically rerun with `-v` to
@@ -214,9 +209,9 @@ style conventions are in separate documents:
    ```makefile
    test:
-    	@go test -timeout 90s -race -cover ./... || \
+    	@go test -timeout 30s -race -cover ./... || \
    		{ echo "--- Rerunning with -v for details ---"; \
-    		  go test -timeout 90s -race -v ./...; exit 1; }
+    		  go test -timeout 30s -race -v ./...; exit 1; }
    ```
    Python example:
@@ -265,10 +260,7 @@ style conventions are in separate documents:
 - `.golangci.yml` is standardized and must _NEVER_ be modified by an agent, only
  manually by the user. Fetch from
-  `https://git.eeqj.de/sneak/prompts/raw/branch/main/.golangci.yml`. The
+  `https://git.eeqj.de/sneak/prompts/raw/branch/main/.golangci.yml`.
  canonical golangci-lint version is v2.12.2 (released 2026-05-06), installed
  commit-pinned via
  `go install github.com/golangci/golangci-lint/v2/cmd/golangci-lint@c0d3ddc9cf3faa61a4e378e879ece580256d76e5`.
 - When pinning images or packages by hash, add a comment above the reference
  with the version and date (YYYY-MM-DD).
@@ -2,43 +2,33 @@
 ## DNS Resolution Tests
-DNS is never mocked in this project, not in tests and not anywhere else; see the
+All resolver tests **MUST** use live queries against real DNS servers.
-README section "No DNS mocking. Ever." Every test that looks something up in DNS
+No mocking of the DNS client layer is permitted.
 **MUST** query live DNS servers, never a stand-in. Logic that works on record
 data, such as comparing or formatting records, may be tested on that data
 directly with no lookup.
 ### Rationale
-The resolver performs iterative resolution from root nameservers through the
+The resolver performs iterative resolution from root nameservers through
-full delegation chain. Mocked responses cannot faithfully represent the variety
+the full delegation chain. Mocked responses cannot faithfully represent
-of real-world DNS behavior (truncation, referrals, glue records, DNSSEC, varied
+the variety of real-world DNS behavior (truncation, referrals, glue
-response times, EDNS, etc.). Testing against real servers ensures the resolver
+records, DNSSEC, varied response times, EDNS, etc.). Testing against
-works correctly in production.
+real servers ensures the resolver works correctly in production.
 ### Constraints
 - Tests hit real DNS infrastructure and require network access
- Test duration depends on network conditions; timeout tuning keeps the suite
+- Test duration depends on network conditions; timeout tuning keeps
-  within the 60-second target
+  the suite within the 30-second target
- Query timeout is calibrated to 3× maximum antipodal RTT (~300ms) plus
+- Query timeout is calibrated to 3× maximum antipodal RTT (~300ms)
-  processing margin
+  plus processing margin
 - Root server fan-out is limited to reduce parallel query load
- Live lookups that expect an answer go through `internal/livednstest`, which
+- Flaky failures from transient network issues are acceptable and
-  limits how many run at once in a test binary and retries a lookup that got
+  should be investigated as potential resolver bugs, not papered over
-  none
+  with mocks or skip flags
 - Flaky failures from transient network issues are acceptable and should be
  investigated as potential resolver bugs, not papered over with mocks or skip
  flags
 ### What NOT to do
- **Do not mock, fake or stub DNS** anywhere: no stand-in `DNSClient`, no
+- **Do not mock `DNSClient`** for resolver tests (the mock constructor
-  stand-in for the watcher's `DNSResolver`, no fake DNS server, no canned
+  exists for unit-testing other packages that consume the resolver)
  responses
 - **Do not add `-short` flags** to skip slow tests
 - **Do not increase `-timeout`** to hide hanging queries
 - **Do not remove `-count=1` from `script/test`** — Go's test cache replays a
  previous run's output without querying anything, so a cached pass is not
  evidence that live resolution works
 - **Do not modify linter configuration** to suppress findings
@@ -1,158 +1,163 @@
 # Workflow
- branch (from `next`)
+* branch (from `main`)
- do the work in Next Step
+* do the work in Next Step
- move Next Step to the top of Completed Steps
+* move Next Step to the top of Completed Steps
- move the top item of Future Steps into Next Step
+* move the top item of Future Steps into Next Step
- commit (`TODO.md` changes in the same commit as the work)
+* commit (`TODO.md` changes in the same commit as the work)
- push
+* merge to `main` if the branch is not protected, otherwise open a PR
- open a PR against `next`
+* push
 # Status
-pre-1.0. No git tags. Work lands on `next` by PR. Open work for 1.0 is tracked
+pre-1.0. No git tags. Core resolver work in flight on feature/resolver
-on the 1.0 milestone: https://git.eeqj.de/sneak/dnswatcher/milestone/7
+(dirty: internal/resolver/resolver_test.go). Local checkout has diverged
 from origin: origin/main is 8 commits ahead (watcher orchestrator,
 unified TARGETS) and origin/feature/resolver already contains the full
 iterative resolver implementation with hermetic mocked tests.
 # Next Step
-trial run of the finished image: https://git.eeqj.de/sneak/dnswatcher/issues/149
+Policy scaffold commit: add LICENSE, REPO_POLICIES.md, .editorconfig,
 .dockerignore, and .gitea/workflows/check.yml, and add the missing
 fmt-check, docker, and hooks targets to the Makefile. One commit, then
 confirm make check still passes.
 # Completed Steps
- 2026-10-02: a record type whose query to a nameserver fails keeps its previous
+- 2026-08-09: `script/cibuild` can no longer report a green it did not
-  records and alerts nothing; the other types are still saved (closes #231).
+  earn. The Dockerfile declares `ARG CHECK_EPOCH` immediately above the
- 2026-10-02: Record Change and Inconsistency notifications list only the record
+  check step and expands it into the `RUN` command, and `script/cibuild`
-  types that differ, each with its values as plain text (closes #219).
+  passes a fresh `$(date +%s%N)` per invocation, so the `make check`
- 2026-10-02: the startup notification no longer says every notification
+  layer is always re-executed while the pinned toolchain install and
-  endpoint works; it says it is a test sent to each of them (closes #230).
+  `go mod download` stay cached. Verified by experiment: before the fix
- 2026-10-02: a Mattermost webhook that answers an HTTP error is logged as
+  a second run on an unchanged tree returned in 283 ms with the check
-  `mattermost notification failed`, not as a Slack failure (closes #227).
+  layer `CACHED`; after it the check runs every time, and a deliberately
- 2026-10-02: durations in the log are written as text such as `2m0s`, not as a
+  planted always-failing test made the build fail with exactly that
-  bare count of nanoseconds (closes #228).
+  test's message
- 2026-10-02: a watched name whose nameservers answer with a CNAME and no
+- 2026-08-07: golangci-lint bumped to v2.12.2 (commit-pinned installs
-  address gets port and TLS checks at the end of its CNAME chain (closes #203).
+  in `Dockerfile` and `script/bootstrap`); `.golangci.yml` set to the
- 2026-10-02: a resolver test that reads one record type from a nameserver's
+  org-standard v2-schema config used across the org's repos
-  answer asks again when that type is missing from it (closes #218).
+  (owner-authorized; same file is being landed as canonical via prompts
- 2026-10-02: a plain `docker build .` of a clone stamps its tag or short
+  PR #24), with settings under `linters.settings` so the
-  commit, not `dev`: the build context now carries `.git` (closes #210).
+  lll/funlen/cyclop/dupl thresholds apply; fixed the resulting
- 2026-10-02: a query a server refuses is not resent asking for recursion, and
+  `goconst`, `dupl`, and `lll` findings; the informational `gomodguard`
-  every root server refusing is reported as DNS interception (closes #206).
+  deprecation warning under this config is accepted
- 2026-10-02: a push to a branch cancels that branch's older CI run, and the
+- 2026-07-07 Adopted scripts-to-rule-them-all: `script/` entrypoints,
-  checkout leaves no token in `.git/config` (closes #216).
+  Makefile shims, README Entrypoints section
- 2026-10-02: watcher tests send far fewer queries and a live attempt may take
+- 2026-02-20: iterative DNS resolver implemented; tests made hermetic
-  18s; nameserver addresses are asked only for A, AAAA, CNAME (closes #214).
+  with mocked DNS (origin/feature/resolver, unmerged)
- 2026-10-02: the resolver tries root servers, and every other server list it
+- 2026-02-20: CI actions and go install refs pinned to commit SHAs;
-  walks, in a random order each time, not always from the top (closes #138).
+  Gitea Actions workflow for make check (origin/ci/make-check, unmerged)
 - 2026-10-02: a name listed more than once in `DNSWATCHER_TARGETS`, in any
  letter case or with a trailing dot, is watched once (closes #207).
 - 2026-10-01: README checked against the code and corrected: metrics, CORS,
  notification retries, CNAMEs, state file fields, Design tree (closes #108).
 - 2026-10-01: a certificate within the expiry warning period is warned about on
  every TLS check, where some checks used to skip it at random (closes #204).
 - 2026-10-01: a domain's NS set is its delegation from the parent zone's
  servers, not whichever of its own servers answered first (closes #200).
 - 2026-10-01: README has Getting Started, Rationale and TODO sections, and its
  Architecture section is now Design, in the order policy sets (closes #173).
 - 2026-10-01: a zone's server that answers SERVFAIL or a referral leading no
  closer is passed over for the next, as one that times out is (closes #197).
 - 2026-10-01: when none of a configured name's nameservers answered, the port
  state saved for its addresses is kept, not removed (closes #193).
 - 2026-10-01: `ResolveIPAddresses` returns an error, not no addresses, when no
  nameserver of the name's zone answered (closes #190).
 - 2026-10-01: `make fmt` and `make fmt-check` cover Markdown with prettier, run
  in Docker at the version pinned by `yarn.lock` (closes #119).
 - 2026-10-01: `make fmt-check` fails on a file `goimports` would change; both
  format scripts run `goimports` at its pinned commit, not from `PATH` (#119).
 - 2026-10-01: a hostname is queried at the servers of the zone it is in, found
  by following delegations for the name, not its last two labels (closes #189).
 - 2026-10-01: each nameserver's addresses are saved with its domain, and a
  change while it stays in the delegation is notified (closes #105).
 - 2026-10-01: the watcher saves state when it stops, and shutdown waits for that
  save, so it no longer relies on the state's own stop hook (closes #114).
 - 2026-10-01: `DNSWATCHER_SENTRY_DSN` reports panics in HTTP handlers to Sentry,
  and a DSN Sentry cannot parse stops startup (closes #107).
 - 2026-10-01: a port or TLS check that shutdown cuts short saves nothing and
  sends no notification, as a cut-short DNS lookup already did (closes #185).
 - 2026-10-01: the client address from `X-Forwarded-For` is the last entry that
  is not a trusted proxy, not the first, which the client sets (closes #181).
 - 2026-10-01: a nameserver that does not answer is saved as `error` with the
  reason, and NS failure and NS recovery are notified (closes #104).
 - 2026-10-01: a `DNSWATCHER_DNS_INTERVAL` or `DNSWATCHER_TLS_INTERVAL` that is
  not a positive duration stops startup; empty means the default (closes #177).
 - 2026-10-01: `/metrics` allows each client address 30 requests a minute,
  counted before Basic Auth, and answers 429 beyond that (closes #101).
 - 2026-10-01: the image built by `make docker` reports the `git describe`
  version, not `dev`, and the startup log now shows it (closes #109).
 - 2026-10-01: two notify shutdown tests always release the delivery they hold,
  so a drain that returns early fails them instead of hanging (closes #176).
 - 2026-10-01: `script/install-precommit` asks git for the repository's git
  directory, so `make hooks` also works where `.git` is a file (closes #129).
 - 2026-10-01: `TODO.md` brought up to date: open issues listed by URL, every
  Completed Steps entry cut to at most two lines (closes #146).
 - 2026-10-01: wildcard CORS now applies only to the public routes, not to
  `/metrics`, and allows only the methods they serve (closes #100).
 - 2026-10-01: `internal/state` and `internal/watcher` no longer export test-only
  constructors: two moved to `export_test.go`, one is deleted (closes #111).
 - 2026-10-01: notify shutdown tests use one timing constant per meaning, name
  the bound they check, and require the drain's debug line (closes #116).
 - 2026-09-29: the entrypoint chowns the data directory to `dnswatcher` and runs
  dnswatcher as that user, so a host bind mount needs no chown (closes #166).
 - 2026-09-29: the live-DNS test package is renamed `internal/livednstest`;
  `make lint` fails when program code imports it (closes #164).
 - 2026-09-29: `.golangci.yml` re-fetched from `sneak/prompts`, with
  `gomodguard_v2` and the org `depguard` `test-support` rule (closes #123).
 - 2026-09-29: watcher and resolver tests that look something up in DNS use the
  real resolver against live DNS servers (closes #159).
 - 2026-09-28: the inconsistency alert is sent once, when two nameservers start
  to disagree; every pair of nameservers is compared (closes #158).
 - 2026-09-28: DNS names in record values (CNAME, MX, SRV and NS targets) are
  lower-cased, so letter case alone is not a change (closes #157).
 - 2026-09-28: lint and tests run on every build: `script/cibuild` and
  `script/docker` pass `--no-cache-filter=lint,builder` (closes #115).
 - 2026-09-28: the server timeout test drives `Run` and checks the timeouts on
  the `http.Server` it serves (closes #120).
 - 2026-09-28: upaas deploy readiness: the image runs as user `dnswatcher` with a
  `HEALTHCHECK`; README "Running under upaas" (closes #147).
 - 2026-09-21: added behavioural tests for `internal/globals`,
  `internal/healthcheck`, and `internal/logger` (closes #110).
 - 2026-09-21: `go mod tidy` dropped the redundant `golang.org/x/sync`
  `// indirect` line so `script/bootstrap` leaves a clean tree (#132)
 - 2026-08-10: comment-only corrections to `script/bootstrap`, `script/cibuild`
  and `Dockerfile.lint`; no behaviour changed.
 - 2026-08-10: MIT `LICENSE` added at the repository root; the README's first
  line and License section name the licence.
 - 2026-08-10: policy scaffold present: `REPO_POLICIES.md`, `.editorconfig`,
  `.dockerignore`, CI workflow, `make fmt-check`, `make docker`, `make hooks`.
 - 2026-08-10: Go's test cache disabled in `script/test` (`-count=1`), so every
  run queries live DNS; a failed run is rerun with `-v`.
 - 2026-08-10: live-DNS tests made robust rather than gated (#93): a limit on
  concurrent lookups, retries, and a quorum across nameservers.
 - 2026-08-10: all linting moved into Docker: `script/lint` builds
  `Dockerfile.lint`, and the root `Dockerfile` has its own lint stage.
 - 2026-08-09: in-flight notification deliveries are drained at shutdown, bounded
  by the shutdown deadline (#106).
 - 2026-08-09: `http.Server` sets all four socket timeouts; `WriteTimeout` stays
  above the 60s handler timeout (#99).
 - 2026-08-09: `SecurityHeaders()` middleware sets HSTS, CSP and the other
  security headers `REPO_POLICIES.md` requires on every response.
 - 2026-08-07: golangci-lint bumped to v2.12.2 and `.golangci.yml` set to the org
  config; fixed the resulting `goconst`, `dupl` and `lll` findings.
 - 2026-07-07 Adopted scripts-to-rule-them-all: `script/` entrypoints, Makefile
  shims, README Entrypoints section
 - 2026-02-20: iterative DNS resolver implemented
 - 2026-02-20: CI actions and go install refs pinned to commit SHAs; Gitea
  Actions workflow added
 - 2026-02-20: watcher monitoring orchestrator merged to main (#8)
 - 2026-02-20: DOMAINS/HOSTNAMES unified into single TARGETS config (#11)
 - 2026-02-19: TCP port connectivity checker, made concurrent with port
  validation; gosec G704 SSRF findings fixed without suppression
- 2026-02-19: TLS certificate inspector with no-peer-certificates error path and
+  (feature branches, unmerged)
-  IP SANs
+- 2026-02-19: TLS certificate inspector with no-peer-certificates error
  path and IP SANs (feature branch, unmerged)
 - 2026-02-19: gosec SSRF and formatting fixes on main
 - 2026-02-19: initial scaffold with per-nameserver DNS monitoring model
 # Future Steps
- 1.0 readiness: run it with a real config and read the logs:
+Compliance:
-  https://git.eeqj.de/sneak/dnswatcher/issues/66
+
- review toward 1.0: https://git.eeqj.de/sneak/dnswatcher/issues/144
+- Add README sections required by policy (Description, Getting Started,
  Rationale, Design, TODO, License, Author) if any are missing
 - Pin Dockerfile base images by sha256 and ensure the Docker build runs
  make check
 Branch reconciliation:
 - Sync local checkout with origin: local main is 8 commits behind
  origin/main; local feature/resolver has diverged from
  origin/feature/resolver, which already implements the resolver
 - Merge in-flight branches to main once green: feature/resolver,
  ci/make-check, feature/portcheck-implementation,
  feature/tlscheck-implementation
 Resolver (plan from untracked TODO.md; largely implemented on
 origin/feature/resolver, verify each item before closing):
 - Add github.com/miekg/dns dependency
 - roots.go: hardcoded IANA root server list (a through m, IPv4/IPv6),
  rootServers() returning ip:53 strings
 - query.go: low-level query(ctx, server, name, qtype): UDP with TCP
  fallback on truncation, RD=0, context respected, 5s per-query timeout,
  returns raw *dns.Msg
 - trace.go: iterative delegation chasing from roots: referral detection
  (NOERROR, empty answer, NS in authority), glue extraction with
  bailiwick check, out-of-bailiwick NS resolved with recursion guard,
  delegation depth limit (20), retry across nameservers on failure, do
  not chase CNAMEs inside trace
 - FindAuthoritativeNameservers: NS set via trace, sorted, FQDN
  normalized, trailing dot handled; must pass its 9 tests
 - QueryNameserver: resolve NS host to IPs, query A/AAAA/CNAME/MX/TXT/
  SRV/CAA/NS, build NameserverResponse with status mapping (OK,
  NXDomain, NoData, Error), documented record formatting, sorted values,
  lame delegation detection; must pass its 16 tests
 - QueryAllNameservers: find NS set for parent domain (public suffix
  list), query all NS in parallel with bounded concurrency, return map
  even when all fail, context cancellation; must pass its 4 tests
 - LookupNS: thin wrapper over FindAuthoritativeNameservers, sorted,
  identical results; must pass its 3 tests
 - ResolveIPAddresses: collect A/AAAA from all NS, follow CNAME chains
  with MaxCNAMEDepth, dedupe, sort, NXDOMAIN returns empty slice with
  nil error; must pass its 9 tests
 - All 39 resolver tests pass, make check green, merge to main
 Watcher (internal/watcher/watcher.go):
 - Scheduling loop in Run(ctx): initial check on startup, separate
  tickers for DNS/port and TLS intervals, persist state via state.Save()
  after each cycle, clean shutdown on context cancel
 - Domain check: LookupNS, compare to stored state, store silently on
  first run, notify with old/new NS lists on change
 - Hostname check: QueryAllNameservers, compare per-NS records; notify on
  record changes, NS failure, NS recovery, inconsistency detected,
  inconsistency resolved, empty response; store silently on first run
 - Port check: ResolveIPAddresses, check ports 80 and 443 per IP, notify
  on open/closed transitions, handle new and disappeared IPs
 - TLS check: for each open IP:443, CheckCertificate; notify on expiry
  warning, certificate change (CN/issuer/SANs), TLS failure/recovery
 Port checker (internal/portcheck/portcheck.go):
 - Tests against known-open ports and RFC documentation IPs
 - CheckPort: net.DialTimeout (5s), context respected; (true, nil) open,
  (false, nil) closed/timeout/refused, error only for unexpected
  failures
 TLS checker (internal/tlscheck/tlscheck.go):
 - Tests against known public HTTPS servers, verify fields populated
 - CheckCertificate: tls.Dial to specific IP:443 with hostname as SNI;
  extract subject CN, issuer CN and org, NotAfter, SANs; error on
  handshake failure
 Notification service (internal/notify/notify.go, Slack/Mattermost/ntfy
 backends exist):
 - Structured notification types: DNS change, port change, TLS expiry,
  TLS change, NS failure, NS recovery, NS inconsistency
 - Per-backend formatting: Slack/Mattermost attachment colors (red
  failures/expiry, yellow warnings, green recoveries, blue info); ntfy
  priorities (urgent failures, high warnings, default changes, low
  recoveries); include hostname, nameserver, old/new values, timestamps
 HTTP API handlers:
 - Wire *state.State and *watcher.Watcher into handler params
 - GET /api/v1/status: full state snapshot as JSON
 - GET /api/v1/domains: domain states with NS records and last-checked
 - GET /api/v1/hostnames: hostname states with per-NS record data
 Infrastructure notes (from untracked TODO.md):
 - Module path sneak.berlin/go/dnswatcher differs from the git.eeqj.de
  remote intentionally; do not "fix" it
 - Dependencies: github.com/miekg/dns, golang.org/x/net/publicsuffix
 - Resolver tests originally used live DNS against *.dns.sneak.cloud
  (required records documented in the test file header); origin now has
  mocked hermetic tests, keep them hermetic
@@ -63,7 +63,6 @@ func main() {
 				return n
 			},
 		),
 		fx.Invoke(func(l *logger.Logger) { l.Identify() }),
 		fx.Invoke(func(*server.Server, *watcher.Watcher) {}),
 	).Run()
 }
@@ -1,17 +0,0 @@
 #!/bin/sh
 # deploy/docker-entrypoint.sh: the Docker image's ENTRYPOINT. It runs as
 # root only to give the data directory to the dnswatcher user: a host
 # directory bind-mounted there keeps its host owner, often root, and may
 # hold a state file left by another uid, which dnswatcher could neither
 # read nor replace. dnswatcher itself always runs as the dnswatcher user.
 set -eu
 main() {
    dir="${DNSWATCHER_DATA_DIR:-/var/lib/dnswatcher}"
    mkdir -p "$dir"
    chown -R dnswatcher:dnswatcher "$dir"
    chmod 700 "$dir"
    exec su-exec dnswatcher /usr/local/bin/dnswatcher "$@"
 }
 main "$@"
@@ -4,30 +4,27 @@ go 1.25.5
 require (
 	github.com/99designs/basicauth-go v0.0.0-20230316000542-bf6f9cbbf0f8
 	github.com/getsentry/sentry-go v0.49.0
 	github.com/go-chi/chi/v5 v5.2.5
 	github.com/go-chi/cors v1.2.2
 	github.com/go-chi/httprate v0.16.0
 	github.com/joho/godotenv v1.5.1
 	github.com/miekg/dns v1.1.72
 	github.com/prometheus/client_golang v1.23.2
 	github.com/spf13/viper v1.21.0
 	github.com/stretchr/testify v1.11.1
 	go.uber.org/fx v1.24.0
-	golang.org/x/net v0.56.0
+	golang.org/x/net v0.50.0
-	golang.org/x/sync v0.21.0
+	golang.org/x/sync v0.19.0
 )
 require (
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
-	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/fsnotify/fsnotify v1.9.0 // indirect
 	github.com/go-viper/mapstructure/v2 v2.4.0 // indirect
 	github.com/klauspost/cpuid/v2 v2.2.10 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/pelletier/go-toml/v2 v2.2.4 // indirect
-	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_model v0.6.2 // indirect
 	github.com/prometheus/common v0.66.1 // indirect
 	github.com/prometheus/procfs v0.16.1 // indirect
@@ -37,16 +34,16 @@ require (
 	github.com/spf13/cast v1.10.0 // indirect
 	github.com/spf13/pflag v1.0.10 // indirect
 	github.com/subosito/gotenv v1.6.0 // indirect
 	github.com/zeebo/xxh3 v1.0.2 // indirect
 	go.uber.org/dig v1.19.0 // indirect
 	go.uber.org/multierr v1.10.0 // indirect
 	go.uber.org/zap v1.26.0 // indirect
 	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
-	golang.org/x/mod v0.37.0 // indirect
+	golang.org/x/mod v0.32.0 // indirect
-	golang.org/x/sys v0.46.0 // indirect
+	golang.org/x/sync v0.19.0 // indirect
-	golang.org/x/text v0.39.0 // indirect
+	golang.org/x/sys v0.41.0 // indirect
-	golang.org/x/tools v0.47.0 // indirect
+	golang.org/x/text v0.34.0 // indirect
 	golang.org/x/tools v0.41.0 // indirect
 	google.golang.org/protobuf v1.36.8 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
@@ -4,22 +4,16 @@ github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
-github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
-github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHkI4W8=
 github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
 github.com/fsnotify/fsnotify v1.9.0 h1:2Ml+OJNzbYCTzsxtv8vKSFD9PbJjmhYF14k/jKC7S9k=
 github.com/fsnotify/fsnotify v1.9.0/go.mod h1:8jBTzvmWwFyi3Pb8djgCCO5IBqzKJ/Jwo8TRcHyHii0=
 github.com/getsentry/sentry-go v0.49.0 h1:Ehejknu1l023Ub7QoRBVLAI7g3Jnhqku4oWx4B4Sh5s=
 github.com/getsentry/sentry-go v0.49.0/go.mod h1:nuMJAoCfe1u0Bts2ocyNI+TW8HT84vRMqwA5Qq/SKUI=
 github.com/go-chi/chi/v5 v5.2.5 h1:Eg4myHZBjyvJmAFjFvWgrqDTXFyOzjj7YIm3L3mu6Ug=
 github.com/go-chi/chi/v5 v5.2.5/go.mod h1:X7Gx4mteadT3eDOMTsXzmI4/rwUpOwBHLpAfupzFJP0=
 github.com/go-chi/cors v1.2.2 h1:Jmey33TE+b+rB7fT8MUy1u0I4L+NARQlK6LhzKPSyQE=
 github.com/go-chi/cors v1.2.2/go.mod h1:sSbTewc+6wYHBBCW7ytsFSn836hqM7JxpglAy2Vzc58=
 github.com/go-chi/httprate v0.16.0 h1:8V5DH9j6pSK6UQoBsTpvMyFxycqaKEIToyPKzHJjUa8=
 github.com/go-chi/httprate v0.16.0/go.mod h1:A8lo+qRhk+s9LiuP5saS7XCGDXRXMcrueq0NfIuCa/I=
 github.com/go-errors/errors v1.4.2 h1:J6MZopCL4uSllY1OfXM374weqZFFItUbrImctkmUxIA=
 github.com/go-errors/errors v1.4.2/go.mod h1:sIVyrIiJhuEF+Pj9Ebtd6P/rEYROXFi3BopGUQ5a5Og=
 github.com/go-viper/mapstructure/v2 v2.4.0 h1:EBsztssimR/CONLSZZ04E8qAkxNYq4Qp9LvH92wZUgs=
 github.com/go-viper/mapstructure/v2 v2.4.0/go.mod h1:oJDH3BJKyqBA2TXFhDsKDGDTlndYOZ6rGS0BRZIxGhM=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
@@ -28,8 +22,6 @@ github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
 github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
 github.com/klauspost/compress v1.18.0 h1:c/Cqfb0r+Yi+JtIEq73FWXVkRonBlf0CRNYc8Zttxdo=
 github.com/klauspost/compress v1.18.0/go.mod h1:2Pp+KzxcywXVXMr50+X0Q/Lsb43OQHYWRCY2AiWywWQ=
 github.com/klauspost/cpuid/v2 v2.2.10 h1:tBs3QSyvjDyFTq3uoc/9xFpCuOsJQFNPiAhYdw2skhE=
 github.com/klauspost/cpuid/v2 v2.2.10/go.mod h1:hqwkgyIinND0mEev00jJYCxPNVRVXFQeu1XKlok6oO0=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
@@ -42,12 +34,8 @@ github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
 github.com/pelletier/go-toml/v2 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0t5Ec4=
 github.com/pelletier/go-toml/v2 v2.2.4/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
-github.com/pingcap/errors v0.11.4 h1:lFuQV/oaUMGcD2tqt+01ROSmJs75VG1ToEOkZIZ4nE4=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
-github.com/pingcap/errors v0.11.4/go.mod h1:Oi8TUi2kEtXXLMJk9l1cGmz20kV3TaQ0usTwv5KuLY8=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
 github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_golang v1.23.2 h1:Je96obch5RDVy3FDMndoUsjAhG5Edi49h0RJWRi/o0o=
 github.com/prometheus/client_golang v1.23.2/go.mod h1:Tb1a6LWHB3/SPIzCoaDXI4I8UHKeFTEQ1YCr+0Gyqmg=
 github.com/prometheus/client_model v0.6.2 h1:oBsgwpGs7iVziMvrGhE53c/GrLUsZdHnqNwqPLxwZyk=
@@ -56,8 +44,8 @@ github.com/prometheus/common v0.66.1 h1:h5E0h5/Y8niHc5DlaLlWLArTQI7tMrsfQjHV+d9Z
 github.com/prometheus/common v0.66.1/go.mod h1:gcaUsgf3KfRSwHY4dIMXLPV0K/Wg1oZ8+SbZk/HH/dA=
 github.com/prometheus/procfs v0.16.1 h1:hZ15bTNuirocR6u0JZ6BAHHmwS1p8B4P6MRqxtzMyRg=
 github.com/prometheus/procfs v0.16.1/go.mod h1:teAbpZRB1iIAJYREa1LsoWUXykVXA1KlTmWl8x/U+Is=
-github.com/rogpeppe/go-internal v1.14.1 h1:UQB4HGPB6osV0SQTLymcB4TgvyWu6ZyliaW0tI/otEQ=
+github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
-github.com/rogpeppe/go-internal v1.14.1/go.mod h1:MaRKkUm5W0goXpeCfT7UZI6fk/L7L7so1lCWt35ZSgc=
+github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
 github.com/sagikazarmark/locafero v0.11.0 h1:1iurJgmM9G3PA/I+wWYIOw/5SyBtxapeHDcg+AAIFXc=
 github.com/sagikazarmark/locafero v0.11.0/go.mod h1:nVIGvgyzw595SUSUE6tvCp3YYTeHs15MvlmU87WwIik=
 github.com/sourcegraph/conc v0.3.1-0.20240121214520-5f936abd7ae8 h1:+jumHNA0Wrelhe64i8F6HNlS8pkoyMv5sreGx2Ry5Rw=
@@ -74,10 +62,6 @@ github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 github.com/subosito/gotenv v1.6.0 h1:9NlTDc1FTs4qu0DDq7AEtTPNw6SVm7uBMsUCUjABIf8=
 github.com/subosito/gotenv v1.6.0/go.mod h1:Dk4QP5c2W3ibzajGcXpNraDfq2IrhjMIvMSWPKKo0FU=
 github.com/zeebo/assert v1.3.0 h1:g7C04CbJuIDKNPFHmsk4hwZDO5O+kntRxzaUoNXj+IQ=
 github.com/zeebo/assert v1.3.0/go.mod h1:Pq9JiuJQpG8JLJdtkwrJESF0Foym2/D9XMU5ciN/wJ0=
 github.com/zeebo/xxh3 v1.0.2 h1:xZmwmqxHZA8AI603jOQ0tMqmBr9lPeFwGg6d+xy9DC0=
 github.com/zeebo/xxh3 v1.0.2/go.mod h1:5NWz9Sef7zIDm2JHfFlcQvNekmcEl9ekUZQQKCYaDcA=
 go.uber.org/dig v1.19.0 h1:BACLhebsYdpQ7IROQ1AGPjrXcP5dF80U3gKoFzbaq/4=
 go.uber.org/dig v1.19.0/go.mod h1:Us0rSJiThwCv2GteUN0Q7OKvU7n5J4dxZ9JKUXozFdE=
 go.uber.org/fx v1.24.0 h1:wE8mruvpg2kiiL1Vqd0CC+tr0/24XIB10Iwp2lLWzkg=
@@ -92,18 +76,18 @@ go.yaml.in/yaml/v2 v2.4.2 h1:DzmwEr2rDGHl7lsFgAHxmNz/1NlQ7xLIrlN2h5d1eGI=
 go.yaml.in/yaml/v2 v2.4.2/go.mod h1:081UH+NErpNdqlCXm3TtEran0rJZGxAYx9hb/ELlsPU=
 go.yaml.in/yaml/v3 v3.0.4 h1:tfq32ie2Jv2UxXFdLJdh3jXuOzWiL1fo0bu/FbuKpbc=
 go.yaml.in/yaml/v3 v3.0.4/go.mod h1:DhzuOOF2ATzADvBadXxruRBLzYTpT36CKvDb3+aBEFg=
-golang.org/x/mod v0.37.0 h1:vF1DjpVEshcIqoEaauuHebaLk1O1forxjxBaVn884JQ=
+golang.org/x/mod v0.32.0 h1:9F4d3PHLljb6x//jOyokMv3eX+YDeepZSEo3mFJy93c=
-golang.org/x/mod v0.37.0/go.mod h1:m8S8VeM9r4dzDwjrKO0a1sZP3YjeMamRRlD+fmR2Q/0=
+golang.org/x/mod v0.32.0/go.mod h1:SgipZ/3h2Ci89DlEtEXWUk/HteuRin+HHhN+WbNhguU=
-golang.org/x/net v0.56.0 h1:Rw8j/hFzGvJUZwNBXnAtf5sVDVt+65SK2C7IxCxZt5o=
+golang.org/x/net v0.50.0 h1:ucWh9eiCGyDR3vtzso0WMQinm2Dnt8cFMuQa9K33J60=
-golang.org/x/net v0.56.0/go.mod h1:D3Ku6r+V6JROoZK144D2XfMHFcMq/0zSfLelVTCFKec=
+golang.org/x/net v0.50.0/go.mod h1:UgoSli3F/pBgdJBHCTc+tp3gmrU4XswgGRgtnwWTfyM=
-golang.org/x/sync v0.21.0 h1:HLII4xRRTtCRkxYp4HNFF0Js/Og6q2i++KXbg0gHCwM=
+golang.org/x/sync v0.19.0 h1:vV+1eWNmZ5geRlYjzm2adRgW2/mcpevXNg50YZtPCE4=
-golang.org/x/sync v0.21.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
+golang.org/x/sync v0.19.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
-golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=
+golang.org/x/sys v0.41.0 h1:Ivj+2Cp/ylzLiEU89QhWblYnOE9zerudt9Ftecq2C6k=
-golang.org/x/sys v0.46.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
+golang.org/x/sys v0.41.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
-golang.org/x/text v0.39.0 h1:UbZz4pLOvn600D6Oh6GGEI6VAmndrEBLv8/6BEXzyus=
+golang.org/x/text v0.34.0 h1:oL/Qq0Kdaqxa1KbNeMKwQq0reLCCaFtqu2eNuSeNHbk=
-golang.org/x/text v0.39.0/go.mod h1:3UwRclnC2g0TU9x8PZiyfOajCd1zaUNHF9cvqcQZ+ZM=
+golang.org/x/text v0.34.0/go.mod h1:homfLqTYRFyVYemLBFl5GgL/DWEiH5wcsQ5gSh1yziA=
-golang.org/x/tools v0.47.0 h1:7Kn5x/d1svx/PzryTsqeoZN4TZwqeH5pGWjefhLi/1Q=
+golang.org/x/tools v0.41.0 h1:a9b8iMweWG+S0OBnlU36rzLp20z1Rp10w+IY2czHTQc=
-golang.org/x/tools v0.47.0/go.mod h1:dFHnyTvFWY212G+h7ZY4Vsp/K3U4/7W9TyVaAul8uCA=
+golang.org/x/tools v0.41.0/go.mod h1:XSY6eDqxVNiYgezAVqqCeihT4j1U2CCsqvH3WhQpnlg=
 google.golang.org/protobuf v1.36.8 h1:xHScyCOEuuwZEc6UtSOvPbAT4zRh0xcNRYekJwfqyMc=
 google.golang.org/protobuf v1.36.8/go.mod h1:fuxRtAxBytpl4zzqUh6/eyUujkJdNiuEkXntxiD/uRU=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
@@ -57,22 +57,17 @@ func ClassifyDNSName(name string) (DNSNameType, error) {
 // ClassifyTargets splits a list of DNS names into apex domains and
 // hostnames using the Public Suffix List. It returns an error if any
-// name cannot be classified. A name given more than once, in any letter
+// name cannot be classified.
 // case or with a trailing dot, is kept once.
 func ClassifyTargets(targets []string) ([]string, []string, error) {
 	var domains, hostnames []string
 	seen := make(map[string]bool)
 	for _, t := range targets {
 		normalized := strings.ToLower(strings.TrimSuffix(strings.TrimSpace(t), "."))
-		if normalized == "" || seen[normalized] {
+		if normalized == "" {
 			continue
 		}
 		seen[normalized] = true
 		typ, classErr := ClassifyDNSName(normalized)
 		if classErr != nil {
 			return nil, nil, classErr
@@ -1,7 +1,6 @@
 package config_test
 import (
 	"slices"
 	"testing"
 	"sneak.berlin/go/dnswatcher/internal/config"
@@ -94,29 +93,6 @@ func TestClassifyTargets(t *testing.T) {
 	}
 }
 func TestClassifyTargetsKeepsEachNameOnce(t *testing.T) {
 	t.Parallel()
 	domains, hostnames, err := config.ClassifyTargets([]string{
 		"example.org",
 		"Example.org.",
 		"www.example.org",
 		"EXAMPLE.ORG",
 		"WWW.Example.org.",
 	})
 	if err != nil {
 		t.Fatalf("unexpected error: %v", err)
 	}
 	if !slices.Equal(domains, []string{"example.org"}) {
 		t.Errorf("domains = %v, want [example.org]", domains)
 	}
 	if !slices.Equal(hostnames, []string{"www.example.org"}) {
 		t.Errorf("hostnames = %v, want [www.example.org]", hostnames)
 	}
 }
 func TestClassifyTargetsRejectsPublicSuffix(t *testing.T) {
 	t.Parallel()
@@ -28,13 +28,6 @@ var ErrNoTargets = errors.New(
 	"no monitoring targets configured: set DNSWATCHER_TARGETS environment variable",
 )
 // ErrInvalidInterval is returned when DNSWATCHER_DNS_INTERVAL or
 // DNSWATCHER_TLS_INTERVAL is set but is not a positive duration. An empty
 // value counts as unset and means the default.
 var ErrInvalidInterval = errors.New(
 	"interval must be a positive duration such as 30m or 1h",
 )
 // Params contains dependencies for Config.
 type Params struct {
 	fx.In
@@ -132,14 +125,18 @@ func buildConfig(
 		}
 	}
-	dnsInterval, err := parseInterval("DNS_INTERVAL")
+	dnsInterval, err := time.ParseDuration(
 		viper.GetString("DNS_INTERVAL"),
 	)
 	if err != nil {
-		return nil, err
+		dnsInterval = defaultDNSInterval
 	}
-	tlsInterval, err := parseInterval("TLS_INTERVAL")
+	tlsInterval, err := time.ParseDuration(
 		viper.GetString("TLS_INTERVAL"),
 	)
 	if err != nil {
-		return nil, err
+		tlsInterval = defaultTLSInterval
 	}
 	domains, hostnames, err := parseAndValidateTargets()
@@ -171,22 +168,6 @@ func buildConfig(
 	return cfg, nil
 }
 // parseInterval reads the DNSWATCHER_-prefixed setting key as a duration. A
 // value that does not parse, or is zero or negative, is an error naming the
 // variable and the value; an unset variable has its default from setupViper.
 func parseInterval(key string) (time.Duration, error) {
 	value := viper.GetString(key)
 	interval, err := time.ParseDuration(value)
 	if err != nil || interval <= 0 {
 		return 0, fmt.Errorf(
 			"invalid DNSWATCHER_%s %q: %w", key, value, ErrInvalidInterval,
 		)
 	}
 	return interval, nil
 }
 func parseAndValidateTargets() ([]string, []string, error) {
 	domains, hostnames, err := ClassifyTargets(
 		parseCSV(viper.GetString("TARGETS")),
@@ -1,7 +1,6 @@
 package config_test
 import (
 	"strconv"
 	"testing"
 	"time"
@@ -114,40 +113,33 @@ func TestNew_OnlyEmptyCSVSegments(t *testing.T) {
 	assert.ErrorIs(t, err, config.ErrNoTargets)
 }
-// TestNew_InvalidIntervalStopsStartup checks values that must stop startup;
+func TestNew_InvalidDNSInterval_FallsBackToDefault(t *testing.T) {
 // TestNew_DefaultValues and TestNew_EmptyIntervalMeansDefault check that an
 // unset or empty interval means the default.
 func TestNew_InvalidIntervalStopsStartup(t *testing.T) {
 	variables := []string{"DNSWATCHER_DNS_INTERVAL", "DNSWATCHER_TLS_INTERVAL"}
 	values := []string{
 		"banana", // not a duration
 		"5",      // no unit
 		"1d",     // days are not a unit time.ParseDuration knows
 		"0",      // zero
 		"-1h",    // negative
 	}
 	for _, variable := range variables {
 		for _, value := range values {
 			t.Run(variable+"="+value, func(t *testing.T) {
 				viper.Reset()
 				t.Setenv("DNSWATCHER_TARGETS", "example.com")
 				t.Setenv(variable, value)
 				_, err := config.New(nil, newTestParams(t))
 				require.ErrorIs(t, err, config.ErrInvalidInterval)
 				require.ErrorContains(t, err, variable)
 				require.ErrorContains(t, err, strconv.Quote(value))
 			})
 		}
 	}
 }
 func TestNew_EmptyIntervalMeansDefault(t *testing.T) {
 	viper.Reset()
 	t.Setenv("DNSWATCHER_TARGETS", "example.com")
-	t.Setenv("DNSWATCHER_DNS_INTERVAL", "")
+	t.Setenv("DNSWATCHER_DNS_INTERVAL", "banana")
-	t.Setenv("DNSWATCHER_TLS_INTERVAL", "")
+
 	cfg, err := config.New(nil, newTestParams(t))
 	require.NoError(t, err)
 	assert.Equal(t, time.Hour, cfg.DNSInterval,
 		"invalid DNS interval should fall back to 1h default")
 }
 func TestNew_InvalidTLSInterval_FallsBackToDefault(t *testing.T) {
 	viper.Reset()
 	t.Setenv("DNSWATCHER_TARGETS", "example.com")
 	t.Setenv("DNSWATCHER_TLS_INTERVAL", "notaduration")
 	cfg, err := config.New(nil, newTestParams(t))
 	require.NoError(t, err)
 	assert.Equal(t, 12*time.Hour, cfg.TLSInterval,
 		"invalid TLS interval should fall back to 12h default")
 }
 func TestNew_BothIntervalsInvalid(t *testing.T) {
 	viper.Reset()
 	t.Setenv("DNSWATCHER_TARGETS", "example.com")
 	t.Setenv("DNSWATCHER_DNS_INTERVAL", "xyz")
 	t.Setenv("DNSWATCHER_TLS_INTERVAL", "abc")
 	cfg, err := config.New(nil, newTestParams(t))
 	require.NoError(t, err)
@@ -1,50 +0,0 @@
 package globals_test
 import (
 	"testing"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"sneak.berlin/go/dnswatcher/internal/globals"
 )
 // TestGlobals exercises the package-level version and appname
 // variables through their setters and read-back via New. These are
 // shared package state, so the test mutates a global and must run
 // sequentially; it cannot use t.Parallel().
 //
 //nolint:paralleltest // mutates shared package-level globals, must run sequentially
 func TestGlobals(t *testing.T) {
 	versions := []string{"v1.2.3", "dev", "", "v1.2.3-4-gabcdef"}
 	for _, want := range versions {
 		globals.SetVersion(want)
 		g, err := globals.New(nil)
 		require.NoError(t, err)
 		assert.Equal(t, want, g.Version,
 			"New must surface the version set by SetVersion")
 	}
 	names := []string{"dnswatcher", "other", ""}
 	for _, want := range names {
 		globals.SetAppname(want)
 		g, err := globals.New(nil)
 		require.NoError(t, err)
 		assert.Equal(t, want, g.Appname,
 			"New must surface the appname set by SetAppname")
 	}
 	// New returns a snapshot: a later SetVersion must not mutate a
 	// Globals handed out earlier.
 	globals.SetVersion("first")
 	g, err := globals.New(nil)
 	require.NoError(t, err)
 	globals.SetVersion("second")
 	assert.Equal(t, "first", g.Version,
 		"a Globals returned by New must not change when the "+
 			"package variable is set again")
 }
@@ -1,134 +0,0 @@
 package healthcheck_test
 import (
 	"context"
 	"encoding/json"
 	"testing"
 	"time"
 	"go.uber.org/fx"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"sneak.berlin/go/dnswatcher/internal/config"
 	"sneak.berlin/go/dnswatcher/internal/globals"
 	"sneak.berlin/go/dnswatcher/internal/healthcheck"
 	"sneak.berlin/go/dnswatcher/internal/logger"
 )
 // recordingLifecycle is a minimal fx.Lifecycle that records the hooks
 // appended to it, so healthcheck.New can be exercised through its real
 // constructor without standing up a whole fx application.
 type recordingLifecycle struct {
 	hooks []fx.Hook
 }
 func (l *recordingLifecycle) Append(hook fx.Hook) {
 	l.hooks = append(l.hooks, hook)
 }
 // newHealthcheck builds a Healthcheck through the real constructor and
 // runs the registered OnStart hook so StartupTime is set the same way
 // the fx lifecycle would set it.
 func newHealthcheck(
 	t *testing.T,
 	maintenance bool,
 	version string,
 ) *healthcheck.Healthcheck {
 	t.Helper()
 	g := &globals.Globals{Appname: "dnswatcher", Version: version}
 	log, err := logger.New(nil, logger.Params{Globals: g})
 	require.NoError(t, err)
 	lifecycle := &recordingLifecycle{}
 	hc, err := healthcheck.New(lifecycle, healthcheck.Params{
 		Globals: g,
 		Config:  &config.Config{MaintenanceMode: maintenance},
 		Logger:  log,
 	})
 	require.NoError(t, err)
 	require.Len(t, lifecycle.hooks, 1,
 		"New must register exactly one lifecycle hook")
 	require.NotNil(t, lifecycle.hooks[0].OnStart)
 	require.NoError(t, lifecycle.hooks[0].OnStart(context.Background()))
 	return hc
 }
 func TestCheckStatusAndPayloadShape(t *testing.T) {
 	t.Parallel()
 	hc := newHealthcheck(t, false, "v9.9.9")
 	resp := hc.Check()
 	assert.Equal(t, "ok", resp.Status)
 	// The JSON shape and field names are part of the contract for the
 	// /health and /.well-known/healthcheck routes, so assert on the
 	// exact set of keys the response marshals to.
 	raw, err := json.Marshal(resp)
 	require.NoError(t, err)
 	var fields map[string]json.RawMessage
 	require.NoError(t, json.Unmarshal(raw, &fields))
 	wantKeys := []string{
 		"status",
 		"now",
 		"uptimeSeconds",
 		"uptimeHuman",
 		"version",
 		"appname",
 		"maintenanceMode",
 	}
 	assert.Len(t, fields, len(wantKeys),
 		"response must marshal to exactly the documented fields")
 	for _, key := range wantKeys {
 		assert.Contains(t, fields, key, "missing JSON field %q", key)
 	}
 	// The Now field is documented as RFC3339Nano; a change to the
 	// format constant should turn this red.
 	_, err = time.Parse(time.RFC3339Nano, resp.Now)
 	assert.NoError(t, err, "Now must be RFC3339Nano")
 }
 func TestCheckMaintenanceModeReflectsConfig(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name        string
 		maintenance bool
 	}{
 		{"maintenance off", false},
 		{"maintenance on", true},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			hc := newHealthcheck(t, tt.maintenance, "test")
 			resp := hc.Check()
 			assert.Equal(t, tt.maintenance, resp.Maintenance,
 				"maintenanceMode must mirror Config.MaintenanceMode")
 		})
 	}
 }
 func TestCheckSurfacesVersionAndAppname(t *testing.T) {
 	t.Parallel()
 	hc := newHealthcheck(t, false, "surfaced-version-123")
 	resp := hc.Check()
 	assert.Equal(t, "surfaced-version-123", resp.Version,
 		"version from globals must appear in the payload")
 	assert.Equal(t, "dnswatcher", resp.Appname)
 }
@@ -1,128 +0,0 @@
 // Package livednstest runs the live DNS operations of tests. Tests that
 // look something up in DNS query live DNS servers, never a stand-in —
 // see TESTING.md. Nothing here mocks, fakes, stubs, records or replays
 // DNS, and nothing here skips a test: it only changes *how* the live
 // queries are issued, so that a single dropped UDP packet or one slow
 // authoritative server does not turn correct code into a red build.
 //
 // Two mechanisms:
 //
 //  1. Bounded concurrency. Tests run in parallel and the build hosts
 //     have many cores, so without a limit every test starts its own
 //     iterative resolution at the same instant and they all send their
 //     first queries to the root servers within a few milliseconds of
 //     each other. Root servers rate-limit that, which shows up as a
 //     different arbitrary subset of tests failing on each run. Run caps
 //     how many live operations are in flight at once in one test binary.
 //
 //  2. Retry with exponential backoff. Each live operation gets several
 //     attempts with its own timeout. An attempt is retried when it
 //     obtained nothing to check, never because of what the test
 //     asserts about the result, so a wrong result still fails on the
 //     first attempt. A fault in the code under test that leaves
 //     nothing to check looks the same as live DNS not answering, and
 //     fails only after the last attempt.
 package livednstest
 import (
 	"context"
 	"errors"
 	"testing"
 	"time"
 )
 const (
 	// attempts is how many times a live DNS operation is attempted
 	// before the test fails.
 	attempts = 3
 	// AttemptTimeout bounds one attempt. It must fit the longest
 	// operation, a watcher check, which sends over a hundred queries one
 	// after another and on a slow build host takes several times as long
 	// as the few seconds it takes on a fast one. An operation whose
 	// every attempt fails takes attempts * AttemptTimeout plus the
 	// backoff, about 56 seconds, after it waits for one of the
 	// Concurrency slots that every live operation in the test binary
 	// shares. So when live DNS does not answer at all, a test binary
 	// with more live operations than slots runs into the 90-second
 	// `go test -timeout` backstop instead of each test failing on its
 	// own.
 	AttemptTimeout = 18 * time.Second
 	// backoffBase is the delay after the first failed attempt; it is
 	// multiplied by backoffFactor each time.
 	backoffBase = 500 * time.Millisecond
 	// backoffFactor is the exponential backoff multiplier.
 	backoffFactor = 2
 	// Concurrency caps how many live operations may be in flight
 	// across one test binary at once.
 	Concurrency = 6
 )
 // gate bounds concurrent live operations. It has to be package scoped:
 // the whole point is that it is shared by every parallel test in the
 // test binary.
 //
 //nolint:gochecknoglobals // package-wide live query rate limit
 var gate = make(chan struct{}, Concurrency)
 // ErrNoAnswer reports that a live operation produced no usable answer,
 // which is retried rather than asserted on.
 var ErrNoAnswer = errors.New("no answer from live DNS")
 // Run executes one attempt of a live operation, holding a slot in gate
 // for its duration and bounding it with its own timeout.
 func Run(op func(ctx context.Context) error) error {
 	gate <- struct{}{}
 	defer func() { <-gate }()
 	ctx, cancel := context.WithTimeout(
 		context.Background(), AttemptTimeout,
 	)
 	defer cancel()
 	return op(ctx)
 }
 // Retry runs op until it reports success, retrying failures with
 // exponential backoff, and fails the test if every attempt fails. op
 // returns an error only for a failure to obtain an answer — never for
 // an answer the test disagrees with, which belongs in an assertion so
 // that it fails immediately. op stores whatever it obtained where its
 // caller can find it.
 func Retry(
 	t *testing.T,
 	what string,
 	op func(ctx context.Context) error,
 ) {
 	t.Helper()
 	var last error
 	backoff := backoffBase
 	for attempt := range attempts {
 		if attempt > 0 {
 			t.Logf(
 				"%s: attempt %d of %d failed (%v), "+
 					"retrying in %s",
 				what, attempt, attempts, last, backoff,
 			)
 			time.Sleep(backoff)
 			backoff *= backoffFactor
 		}
 		last = Run(op)
 		if last == nil {
 			return
 		}
 	}
 	t.Fatalf(
 		"%s: all %d live attempts failed: %v",
 		what, attempts, last,
 	)
 }
@@ -1,103 +0,0 @@
 package livednstest_test
 import (
 	"context"
 	"sync"
 	"testing"
 	"time"
 	"github.com/stretchr/testify/assert"
 	"sneak.berlin/go/dnswatcher/internal/livednstest"
 )
 // Tests for the retry and the concurrency limit themselves. They
 // perform no DNS resolution of any kind.
 func TestRetryRecoversFromTransientFailure(t *testing.T) {
 	t.Parallel()
 	const wantAttempts = 2
 	attempts := 0
 	livednstest.Retry(t, "transient", func(_ context.Context) error {
 		attempts++
 		if attempts < wantAttempts {
 			return livednstest.ErrNoAnswer
 		}
 		return nil
 	})
 	assert.Equal(t, wantAttempts, attempts)
 }
 func TestRetryGivesEachAttemptADeadline(t *testing.T) {
 	t.Parallel()
 	livednstest.Retry(t, "deadline", func(ctx context.Context) error {
 		deadline, ok := ctx.Deadline()
 		assert.True(t, ok, "attempt should carry a deadline")
 		remaining := time.Until(deadline)
 		assert.LessOrEqual(t, remaining, livednstest.AttemptTimeout)
 		// Lower bound too: without one this passes for a
 		// deadline far shorter than intended, which would
 		// silently turn every live attempt into an instant
 		// timeout.
 		assert.Greater(t, remaining, livednstest.AttemptTimeout/2)
 		return nil
 	})
 }
 func TestRunBoundsConcurrency(t *testing.T) {
 	t.Parallel()
 	const workers = 24
 	var (
 		mu       sync.Mutex
 		wg       sync.WaitGroup
 		inFlight int
 		maxSeen  int
 	)
 	wg.Add(workers)
 	for range workers {
 		go func() {
 			defer wg.Done()
 			_ = livednstest.Run(func(_ context.Context) error {
 				mu.Lock()
 				inFlight++
 				if inFlight > maxSeen {
 					maxSeen = inFlight
 				}
 				mu.Unlock()
 				time.Sleep(time.Millisecond)
 				mu.Lock()
 				inFlight--
 				mu.Unlock()
 				return nil
 			})
 		}()
 	}
 	wg.Wait()
 	assert.Positive(t, maxSeen)
 	assert.LessOrEqual(
 		t, maxSeen, livednstest.Concurrency,
 		"live queries must stay under the package-wide gate",
 	)
 }
@@ -1,66 +0,0 @@
 package logger_test
 import (
 	"context"
 	"log/slog"
 	"testing"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"sneak.berlin/go/dnswatcher/internal/globals"
 	"sneak.berlin/go/dnswatcher/internal/logger"
 )
 func newTestLogger(t *testing.T) *logger.Logger {
 	t.Helper()
 	g := &globals.Globals{Appname: "dnswatcher", Version: "test"}
 	l, err := logger.New(nil, logger.Params{Globals: g})
 	require.NoError(t, err)
 	return l
 }
 // TestNewReturnsUsableLogger checks that the constructor yields a
 // working *slog.Logger.
 func TestNewReturnsUsableLogger(t *testing.T) {
 	t.Parallel()
 	l := newTestLogger(t)
 	require.NotNil(t, l.Get(), "Get must return a non-nil logger")
 }
 // TestDefaultLevelExcludesDebug verifies the default configuration
 // logs at info: debug records are suppressed, info records pass.
 func TestDefaultLevelExcludesDebug(t *testing.T) {
 	t.Parallel()
 	log := newTestLogger(t).Get()
 	ctx := context.Background()
 	assert.False(t, log.Enabled(ctx, slog.LevelDebug),
 		"debug must be suppressed at the default level")
 	assert.True(t, log.Enabled(ctx, slog.LevelInfo),
 		"info must be enabled at the default level")
 }
 // TestEnableDebugLoggingChangesLevel verifies the debug and non-debug
 // configurations differ as intended: enabling debug makes debug
 // records pass where they previously did not.
 func TestEnableDebugLoggingChangesLevel(t *testing.T) {
 	t.Parallel()
 	l := newTestLogger(t)
 	log := l.Get()
 	ctx := context.Background()
 	require.False(t, log.Enabled(ctx, slog.LevelDebug),
 		"debug must start disabled")
 	l.EnableDebugLogging()
 	assert.True(t, log.Enabled(ctx, slog.LevelDebug),
 		"debug must be enabled after EnableDebugLogging")
 }
@@ -1,19 +0,0 @@
 package middleware
 import (
 	"net/http"
 	"time"
 )
 // The /metrics rate limit, exported so the tests can count requests
 // against it.
 const (
 	MetricsRequestLimit                = metricsRequestLimit
 	MetricsRequestWindow time.Duration = metricsRequestWindow
 )
 // RealIP is realIP, exported so the tests can check which address it
 // takes as the client's.
 func RealIP(r *http.Request) string {
 	return realIP(r)
 }
@@ -5,14 +5,12 @@ import (
 	"log/slog"
 	"net"
 	"net/http"
 	"net/netip"
 	"strings"
 	"time"
 	"github.com/99designs/basicauth-go"
 	"github.com/go-chi/chi/v5/middleware"
 	"github.com/go-chi/cors"
 	"github.com/go-chi/httprate"
 	"go.uber.org/fx"
 	"sneak.berlin/go/dnswatcher/internal/config"
@@ -23,71 +21,6 @@ import (
 // corsMaxAge is the maximum age for CORS preflight responses.
 const corsMaxAge = 300
 // Rate limit for /metrics: each client address may send
 // metricsRequestLimit requests per metricsRequestWindow. Every request
 // counts, so password guessing gets at most 30 tries a minute per
 // address. One Prometheus server scraping every 15 seconds sends 4
 // requests a minute, and two scraping every 5 seconds from one address
 // send 24, so normal scraping stays under the limit.
 const (
 	metricsRequestLimit  = 30
 	metricsRequestWindow = time.Minute
 )
 // Security response header values applied to every response.
 //
 // The CSP is as strict as the dashboard allows: the template ships no
 // JavaScript, no inline styles, no inline event handlers and no images,
 // and its only subresource is the embedded stylesheet at
 // /s/css/tailwind.min.css, which style-src 'self' permits. Neither
 // unsafe-inline nor unsafe-eval is used. frame-ancestors 'none' is the
 // primary anti-framing control; X-Frame-Options is the legacy fallback.
 const (
 	// hstsValue is emitted unconditionally, including over plain HTTP,
 	// because the service runs behind a TLS-terminating proxy and the
 	// browser must still enforce HTTPS end to end.
 	hstsValue = "max-age=31536000; includeSubDomains"
 	cspValue = "default-src 'self'; " +
 		"script-src 'none'; " +
 		"style-src 'self'; " +
 		"img-src 'self'; " +
 		"font-src 'none'; " +
 		"connect-src 'none'; " +
 		"object-src 'none'; " +
 		"base-uri 'none'; " +
 		"form-action 'none'; " +
 		"frame-ancestors 'none'"
 	frameOptionsValue = "DENY"
 	contentTypeOptionsValue = "nosniff"
 	// referrerPolicyValue is stricter than the policy minimum of
 	// strict-origin-when-cross-origin: the dashboard has no
 	// cross-origin navigation needs and its URL may name internal
 	// hosts.
 	referrerPolicyValue = "no-referrer"
 	permissionsPolicyValue = "accelerometer=(), " +
 		"autoplay=(), " +
 		"camera=(), " +
 		"display-capture=(), " +
 		"encrypted-media=(), " +
 		"fullscreen=(), " +
 		"geolocation=(), " +
 		"gyroscope=(), " +
 		"magnetometer=(), " +
 		"microphone=(), " +
 		"midi=(), " +
 		"payment=(), " +
 		"picture-in-picture=(), " +
 		"publickey-credentials-get=(), " +
 		"screen-wake-lock=(), " +
 		"usb=(), " +
 		"xr-spatial-tracking=()"
 )
 // Params contains dependencies for Middleware.
 type Params struct {
 	fx.In
@@ -209,12 +142,6 @@ func isTrustedProxy(ip net.IP) bool {
 // realIP extracts the client's real IP address from the request.
 // Proxy headers are only trusted from RFC1918/loopback addresses.
 //
 // Each proxy adds to the end of X-Forwarded-For the address it got the
 // request from, so the client can write every entry before the one the
 // first trusted proxy added. The client address is therefore the
 // rightmost entry that is not a trusted proxy, or the leftmost entry
 // when they all are.
 func realIP(r *http.Request) string {
 	addr := ipFromHostPort(r.RemoteAddr)
 	remoteIP := net.ParseIP(addr)
@@ -229,100 +156,36 @@ func realIP(r *http.Request) string {
 		return ip
 	}
-	// A proxy may add its entry as a header line of its own instead of
+	if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
-	// appending to the line the client sent, so all lines form one list.
+		if parts := strings.SplitN(
-	entries := strings.Split(
+			xff, ",", 2, //nolint:mnd
-		strings.Join(r.Header.Values("X-Forwarded-For"), ","), ",",
+		); len(parts) > 0 {
-	)
+			if ip := strings.TrimSpace(parts[0]); ip != "" {
-	client := strings.TrimSpace(entries[0])
+				return ip
-
+			}
 	for i := len(entries) - 1; i > 0; i-- {
 		entry := strings.TrimSpace(entries[i])
 		if !isTrustedProxy(net.ParseIP(entry)) {
 			client = entry
 			break
 		}
 	}
 	if client != "" {
 		return client
 	}
 	return addr
 }
-// CORS returns middleware that lets any origin read a response. It is
+// CORS returns CORS middleware.
 // for the public, read-only routes only, so it allows only the
 // methods those routes serve and no Authorization header.
 func (m *Middleware) CORS() func(http.Handler) http.Handler {
 	return cors.Handler(cors.Options{
-		AllowedOrigins:   []string{"*"},
+		AllowedOrigins: []string{"*"},
-		AllowedMethods:   []string{"GET", "OPTIONS"},
+		AllowedMethods: []string{
-		AllowedHeaders:   []string{"Accept", "Content-Type"},
+			"GET", "POST", "PUT", "DELETE", "OPTIONS",
 		},
 		AllowedHeaders: []string{
 			"Accept", "Authorization",
 			"Content-Type", "X-CSRF-Token",
 		},
 		ExposedHeaders:   []string{"Link"},
 		AllowCredentials: false,
 		MaxAge:           corsMaxAge,
 	})
 }
 // SecurityHeaders returns middleware that sets the security response
 // headers required for production internet exposure on every response.
 //
 // The headers are set before the request reaches the next handler so
 // that they are present on every response, including panics recovered
 // by chi's Recoverer and timeouts produced by chi's Timeout.
 func (m *Middleware) SecurityHeaders() func(http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(
 			writer http.ResponseWriter,
 			request *http.Request,
 		) {
 			header := writer.Header()
 			header.Set("Strict-Transport-Security", hstsValue)
 			header.Set("Content-Security-Policy", cspValue)
 			header.Set("X-Frame-Options", frameOptionsValue)
 			header.Set(
 				"X-Content-Type-Options",
 				contentTypeOptionsValue,
 			)
 			header.Set("Referrer-Policy", referrerPolicyValue)
 			header.Set(
 				"Permissions-Policy",
 				permissionsPolicyValue,
 			)
 			next.ServeHTTP(writer, request)
 		})
 	}
 }
 // MetricsRateLimit returns middleware for /metrics that answers 429
 // Too Many Requests to a client address over the rate limit. The
 // address is the one realIP works out, so a client that is not a
 // trusted proxy cannot get a fresh allowance by sending its own
 // X-Real-IP or X-Forwarded-For. CanonicalizeIP counts all IPv6
 // addresses in one /64 as one client, since a client usually holds a
 // whole /64. An IPv4 address a proxy reports in IPv6-mapped form
 // (::ffff:203.0.113.1) is turned back into plain IPv4 first, as every
 // such address is in the same /64.
 func (m *Middleware) MetricsRateLimit() func(http.Handler) http.Handler {
 	return httprate.LimitBy(
 		metricsRequestLimit,
 		metricsRequestWindow,
 		func(request *http.Request) (string, error) {
 			ip := realIP(request)
 			addr, err := netip.ParseAddr(ip)
 			if err == nil {
 				ip = addr.Unmap().String()
 			}
 			return httprate.CanonicalizeIP(ip), nil
 		},
 	)
 }
 // MetricsAuth returns basic auth middleware for /metrics.
 func (m *Middleware) MetricsAuth() func(http.Handler) http.Handler {
 	if m.params.Config.MetricsUsername == "" {
@@ -1,565 +0,0 @@
 package middleware_test
 import (
 	"net/http"
 	"net/http/httptest"
 	"strings"
 	"testing"
 	"time"
 	"github.com/go-chi/chi/v5"
 	"go.uber.org/fx/fxtest"
 	"sneak.berlin/go/dnswatcher/internal/config"
 	"sneak.berlin/go/dnswatcher/internal/globals"
 	"sneak.berlin/go/dnswatcher/internal/handlers"
 	"sneak.berlin/go/dnswatcher/internal/logger"
 	"sneak.berlin/go/dnswatcher/internal/middleware"
 	"sneak.berlin/go/dnswatcher/internal/notify"
 	"sneak.berlin/go/dnswatcher/internal/state"
 )
 // Expected security header values, spelled out literally so that any
 // change to the middleware has to be made deliberately here as well.
 const (
 	wantHSTS = "max-age=31536000; includeSubDomains"
 	wantCSP = "default-src 'self'; " +
 		"script-src 'none'; " +
 		"style-src 'self'; " +
 		"img-src 'self'; " +
 		"font-src 'none'; " +
 		"connect-src 'none'; " +
 		"object-src 'none'; " +
 		"base-uri 'none'; " +
 		"form-action 'none'; " +
 		"frame-ancestors 'none'"
 	wantFrameOptions = "DENY"
 	wantContentTypeOptions = "nosniff"
 	wantReferrerPolicy = "no-referrer"
 	wantPermissionsPolicy = "accelerometer=(), " +
 		"autoplay=(), " +
 		"camera=(), " +
 		"display-capture=(), " +
 		"encrypted-media=(), " +
 		"fullscreen=(), " +
 		"geolocation=(), " +
 		"gyroscope=(), " +
 		"magnetometer=(), " +
 		"microphone=(), " +
 		"midi=(), " +
 		"payment=(), " +
 		"picture-in-picture=(), " +
 		"publickey-credentials-get=(), " +
 		"screen-wake-lock=(), " +
 		"usb=(), " +
 		"xr-spatial-tracking=()"
 )
 // stylesheetPath is the only subresource the dashboard loads.
 const stylesheetPath = "/s/css/tailwind.min.css"
 // newTestLogger builds a logger for direct component construction.
 func newTestLogger(t *testing.T) *logger.Logger {
 	t.Helper()
 	glob, err := globals.New(nil)
 	if err != nil {
 		t.Fatalf("globals.New: %v", err)
 	}
 	log, err := logger.New(nil, logger.Params{Globals: glob})
 	if err != nil {
 		t.Fatalf("logger.New: %v", err)
 	}
 	return log
 }
 // newTestMiddleware builds a Middleware without an fx application.
 func newTestMiddleware(t *testing.T) *middleware.Middleware {
 	t.Helper()
 	glob, err := globals.New(nil)
 	if err != nil {
 		t.Fatalf("globals.New: %v", err)
 	}
 	mw, err := middleware.New(nil, middleware.Params{
 		Logger:  newTestLogger(t),
 		Globals: glob,
 		Config:  &config.Config{},
 	})
 	if err != nil {
 		t.Fatalf("middleware.New: %v", err)
 	}
 	return mw
 }
 // serveWithSecurityHeaders runs a GET through SecurityHeaders and
 // returns the recorded response.
 func serveWithSecurityHeaders(
 	t *testing.T,
 	target string,
 	handler http.Handler,
 ) *httptest.ResponseRecorder {
 	t.Helper()
 	mw := newTestMiddleware(t)
 	rec := httptest.NewRecorder()
 	req := httptest.NewRequestWithContext(
 		t.Context(), http.MethodGet, target, nil,
 	)
 	mw.SecurityHeaders()(handler).ServeHTTP(rec, req)
 	return rec
 }
 // okHandler writes a trivial 200 response.
 func okHandler() http.Handler {
 	return http.HandlerFunc(func(
 		writer http.ResponseWriter,
 		_ *http.Request,
 	) {
 		writer.WriteHeader(http.StatusOK)
 	})
 }
 func TestSecurityHeaders(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name   string
 		header string
 		want   string
 	}{
 		{
 			"hsts",
 			"Strict-Transport-Security",
 			wantHSTS,
 		},
 		{
 			"csp",
 			"Content-Security-Policy",
 			wantCSP,
 		},
 		{
 			"frame options",
 			"X-Frame-Options",
 			wantFrameOptions,
 		},
 		{
 			"content type options",
 			"X-Content-Type-Options",
 			wantContentTypeOptions,
 		},
 		{
 			"referrer policy",
 			"Referrer-Policy",
 			wantReferrerPolicy,
 		},
 		{
 			"permissions policy",
 			"Permissions-Policy",
 			wantPermissionsPolicy,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			rec := serveWithSecurityHeaders(t, "/", okHandler())
 			got := rec.Header().Get(tt.header)
 			if got != tt.want {
 				t.Errorf(
 					"%s = %q, want %q",
 					tt.header, got, tt.want,
 				)
 			}
 		})
 	}
 }
 // TestSecurityHeadersCSPDirectives guards the properties the repo
 // policy requires of the content security policy itself.
 func TestSecurityHeadersCSPDirectives(t *testing.T) {
 	t.Parallel()
 	rec := serveWithSecurityHeaders(t, "/", okHandler())
 	csp := rec.Header().Get("Content-Security-Policy")
 	forbidden := []string{"unsafe-inline", "unsafe-eval"}
 	for _, directive := range forbidden {
 		if strings.Contains(csp, directive) {
 			t.Errorf("CSP must not contain %q: %q", directive, csp)
 		}
 	}
 	required := []string{
 		"default-src 'self'",
 		"script-src 'none'",
 		"style-src 'self'",
 		"frame-ancestors 'none'",
 	}
 	for _, directive := range required {
 		if !strings.Contains(csp, directive) {
 			t.Errorf("CSP must contain %q: %q", directive, csp)
 		}
 	}
 }
 // TestSecurityHeadersOnErrorResponse verifies the headers are emitted
 // even when the wrapped handler fails, since they are set before the
 // handler runs.
 func TestSecurityHeadersOnErrorResponse(t *testing.T) {
 	t.Parallel()
 	failing := http.HandlerFunc(func(
 		writer http.ResponseWriter,
 		_ *http.Request,
 	) {
 		http.Error(
 			writer,
 			"boom",
 			http.StatusInternalServerError,
 		)
 	})
 	rec := serveWithSecurityHeaders(t, "/api/v1/status", failing)
 	if rec.Code != http.StatusInternalServerError {
 		t.Fatalf("status = %d, want 500", rec.Code)
 	}
 	if got := rec.Header().Get(
 		"X-Content-Type-Options",
 	); got != wantContentTypeOptions {
 		t.Errorf(
 			"X-Content-Type-Options = %q, want %q",
 			got, wantContentTypeOptions,
 		)
 	}
 	if got := rec.Header().Get(
 		"Strict-Transport-Security",
 	); got != wantHSTS {
 		t.Errorf(
 			"Strict-Transport-Security = %q, want %q",
 			got, wantHSTS,
 		)
 	}
 }
 // newTestHandlers builds real Handlers with empty monitoring state.
 func newTestHandlers(t *testing.T) *handlers.Handlers {
 	t.Helper()
 	glob, err := globals.New(nil)
 	if err != nil {
 		t.Fatalf("globals.New: %v", err)
 	}
 	log := newTestLogger(t)
 	notifier, err := notify.New(fxtest.NewLifecycle(t), notify.Params{
 		Logger: log,
 		Config: &config.Config{},
 	})
 	if err != nil {
 		t.Fatalf("notify.New: %v", err)
 	}
 	st, err := state.New(fxtest.NewLifecycle(t), state.Params{
 		Logger: log,
 		Config: &config.Config{DataDir: t.TempDir()},
 	})
 	if err != nil {
 		t.Fatalf("state.New: %v", err)
 	}
 	hnd, err := handlers.New(nil, handlers.Params{
 		Logger:  log,
 		Globals: glob,
 		State:   st,
 		Notify:  notifier,
 	})
 	if err != nil {
 		t.Fatalf("handlers.New: %v", err)
 	}
 	return hnd
 }
 // TestDashboardRendersWithSecurityHeaders renders the real dashboard
 // through the middleware and checks that the policy still permits the
 // one stylesheet the page loads.
 func TestDashboardRendersWithSecurityHeaders(t *testing.T) {
 	t.Parallel()
 	mw := newTestMiddleware(t)
 	hnd := newTestHandlers(t)
 	router := chi.NewRouter()
 	router.Use(mw.SecurityHeaders())
 	router.Get("/", hnd.HandleDashboard())
 	rec := httptest.NewRecorder()
 	req := httptest.NewRequestWithContext(
 		t.Context(), http.MethodGet, "/", nil,
 	)
 	router.ServeHTTP(rec, req)
 	if rec.Code != http.StatusOK {
 		t.Fatalf("status = %d, want 200", rec.Code)
 	}
 	body := rec.Body.String()
 	if !strings.Contains(body, stylesheetPath) {
 		t.Errorf("dashboard does not reference %q", stylesheetPath)
 	}
 	if !strings.Contains(body, "dnswatcher") {
 		t.Errorf("dashboard body looks empty: %d bytes", len(body))
 	}
 	csp := rec.Header().Get("Content-Security-Policy")
 	if csp != wantCSP {
 		t.Errorf("CSP = %q, want %q", csp, wantCSP)
 	}
 	// The stylesheet is same-origin, so style-src 'self' allows it.
 	if !strings.Contains(csp, "style-src 'self'") {
 		t.Errorf("CSP would block %q: %q", stylesheetPath, csp)
 	}
 }
 // Addresses for the rate limit and realIP tests: a client connecting
 // directly, a trusted proxy, and a client behind that proxy as the
 // proxy's X-Real-IP or X-Forwarded-For header names it.
 const (
 	directClient  = "198.51.100.1:4000"
 	trustedProxy  = "10.0.0.1:4000"
 	proxiedClient = "203.0.113.1"
 )
 // statusFrom sends a GET through handler as if from remoteAddr, with
 // an X-Real-IP header when xRealIP is not empty, and returns the
 // response status.
 func statusFrom(
 	t *testing.T,
 	handler http.Handler,
 	remoteAddr string,
 	xRealIP string,
 ) int {
 	t.Helper()
 	req := httptest.NewRequestWithContext(
 		t.Context(), http.MethodGet, "/metrics", nil,
 	)
 	req.RemoteAddr = remoteAddr
 	if xRealIP != "" {
 		req.Header.Set("X-Real-IP", xRealIP)
 	}
 	rec := httptest.NewRecorder()
 	handler.ServeHTTP(rec, req)
 	return rec.Code
 }
 // TestMetricsRateLimitAllowsScraping checks that one address can send,
 // within one window, what two Prometheus servers scraping every 5
 // seconds send in that time, without being turned away.
 func TestMetricsRateLimitAllowsScraping(t *testing.T) {
 	t.Parallel()
 	const scrapeInterval = 5 * time.Second
 	scrapes := 2 * int(middleware.MetricsRequestWindow/scrapeInterval)
 	limited := newTestMiddleware(t).MetricsRateLimit()(okHandler())
 	for i := range scrapes {
 		got := statusFrom(t, limited, directClient, "")
 		if got != http.StatusOK {
 			t.Fatalf(
 				"scrape %d of %d: status = %d, want 200",
 				i+1, scrapes, got,
 			)
 		}
 	}
 }
 // TestMetricsRateLimitKeysOnClientAddress checks which requests share
 // an allowance. Each case uses up the allowance of one client, then
 // sends one more request.
 func TestMetricsRateLimitKeysOnClientAddress(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name           string
 		usedRemoteAddr string
 		usedXRealIP    string
 		nextRemoteAddr string
 		nextXRealIP    string
 		want           int
 	}{
 		{
 			"same address",
 			directClient, "",
 			directClient, "",
 			http.StatusTooManyRequests,
 		},
 		{
 			"another address",
 			directClient, "",
 			"198.51.100.2:4000", "",
 			http.StatusOK,
 		},
 		{
 			"own X-Real-IP from an untrusted address",
 			directClient, "",
 			directClient, "203.0.113.9",
 			http.StatusTooManyRequests,
 		},
 		{
 			"same client behind the proxy",
 			trustedProxy, proxiedClient,
 			trustedProxy, proxiedClient,
 			http.StatusTooManyRequests,
 		},
 		{
 			"another client behind the proxy",
 			trustedProxy, proxiedClient,
 			trustedProxy, "203.0.113.2",
 			http.StatusOK,
 		},
 		{
 			"another client behind the proxy, IPv6-mapped",
 			trustedProxy, "::ffff:203.0.113.1",
 			trustedProxy, "::ffff:203.0.113.2",
 			http.StatusOK,
 		},
 		{
 			"same IPv6 /64",
 			"[2001:db8::1]:4000", "",
 			"[2001:db8::2]:4000", "",
 			http.StatusTooManyRequests,
 		},
 		{
 			"another IPv6 /64",
 			"[2001:db8::1]:4000", "",
 			"[2001:db8:0:1::1]:4000", "",
 			http.StatusOK,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			limited := newTestMiddleware(t).MetricsRateLimit()(okHandler())
 			for range middleware.MetricsRequestLimit {
 				statusFrom(t, limited, tt.usedRemoteAddr, tt.usedXRealIP)
 			}
 			got := statusFrom(
 				t, limited, tt.nextRemoteAddr, tt.nextXRealIP,
 			)
 			if got != tt.want {
 				t.Errorf("status = %d, want %d", got, tt.want)
 			}
 		})
 	}
 }
 // TestRealIP checks which address realIP takes as the client's. Each
 // element of forwardedFor is sent as an X-Forwarded-For header line of
 // its own, and 198.51.100.9 is always an entry the client wrote itself.
 func TestRealIP(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name         string
 		remoteAddr   string
 		xRealIP      string
 		forwardedFor []string
 		want         string
 	}{
 		{
 			"untrusted peer, both headers ignored",
 			directClient, proxiedClient, []string{"198.51.100.9"},
 			"198.51.100.1",
 		},
 		{
 			"X-Real-IP from a trusted proxy wins",
 			trustedProxy, proxiedClient, []string{"203.0.113.8"},
 			proxiedClient,
 		},
 		{
 			"client's own entry, then the one the proxy added",
 			trustedProxy, "", []string{"198.51.100.9, 203.0.113.1"},
 			proxiedClient,
 		},
 		{
 			"several trusted proxies",
 			trustedProxy, "",
 			[]string{"198.51.100.9, 203.0.113.1, 10.0.0.3, 10.0.0.2"},
 			proxiedClient,
 		},
 		{
 			"proxy adds a header line of its own",
 			trustedProxy, "", []string{"198.51.100.9", proxiedClient},
 			proxiedClient,
 		},
 		{
 			"every entry a trusted proxy",
 			trustedProxy, "", []string{"10.0.0.3, 10.0.0.2"},
 			"10.0.0.3",
 		},
 		{
 			"empty where the client address belongs",
 			trustedProxy, "", []string{"203.0.113.1, , 10.0.0.2"},
 			"10.0.0.1",
 		},
 		{
 			"no headers from a trusted proxy",
 			trustedProxy, "", nil,
 			"10.0.0.1",
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			req := httptest.NewRequestWithContext(
 				t.Context(), http.MethodGet, "/", nil,
 			)
 			req.RemoteAddr = tt.remoteAddr
 			if tt.xRealIP != "" {
 				req.Header.Set("X-Real-IP", tt.xRealIP)
 			}
 			for _, line := range tt.forwardedFor {
 				req.Header.Add("X-Forwarded-For", line)
 			}
 			got := middleware.RealIP(req)
 			if got != tt.want {
 				t.Errorf("realIP = %q, want %q", got, tt.want)
 			}
 		})
 	}
 }
@@ -6,11 +6,9 @@ import (
 	"encoding/json"
 	"errors"
 	"io"
 	"maps"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
 	"strings"
 	"sync"
 	"testing"
 	"time"
@@ -415,8 +413,7 @@ func sendSlackInfo(
 	svc *notify.Service, target *url.URL,
 ) error {
 	return svc.SendSlack(
-		context.Background(), target, notify.ErrSlackFailed,
+		context.Background(), target, "t", "m", prioInfo,
 		"t", "m", prioInfo,
 	)
 }
@@ -509,7 +506,6 @@ func TestSendSlackPayloadFields(t *testing.T) {
 	err := svc.SendSlack(
 		context.Background(),
 		webhookURL,
 		notify.ErrSlackFailed,
 		"Alert Title",
 		"Alert body text",
 		"warning",
@@ -612,8 +608,7 @@ func TestSendSlackAllColors(t *testing.T) {
 			err := svc.SendSlack(
 				context.Background(),
-				webhookURL, notify.ErrSlackFailed,
+				webhookURL, "t", "m", tc.priority,
 				"t", "m", tc.priority,
 			)
 			if err != nil {
 				t.Fatalf("SendSlack error: %v", err)
@@ -664,8 +659,7 @@ func TestSendSlackNetworkError(t *testing.T) {
 	)
 	err := svc.SendSlack(
-		context.Background(), webhookURL, notify.ErrSlackFailed,
+		context.Background(), webhookURL, "t", "m", "info",
 		"t", "m", "info",
 	)
 	if err == nil {
 		t.Fatal("expected error for network failure")
@@ -1034,66 +1028,6 @@ func TestSendNotificationMattermostError(t *testing.T) {
 	)
 }
 // TestSendNotificationErrorNamesEndpoint verifies that, with both
 // Slack and Mattermost set, a failed delivery's logged error names
 // the endpoint that failed. Both are sent by the Slack sender.
 func TestSendNotificationErrorNamesEndpoint(t *testing.T) {
 	t.Parallel()
 	srv := httptest.NewServer(
 		http.HandlerFunc(
 			func(w http.ResponseWriter, _ *http.Request) {
 				w.WriteHeader(http.StatusServiceUnavailable)
 			}),
 	)
 	defer srv.Close()
 	target, _ := url.Parse(srv.URL)
 	svc, logs := newLoggingService(http.DefaultTransport)
 	svc.SetSlackWebhookURL(target)
 	svc.SetMattermostWebhookURL(target)
 	svc.SetSleepFunc(instantSleep)
 	svc.SetRetryConfig(notify.RetryConfig{
 		MaxRetries: 1,
 		BaseDelay:  time.Millisecond,
 		MaxDelay:   time.Millisecond,
 	})
 	svc.SendNotification(
 		context.Background(), "t", "m", prioError,
 	)
 	waitForCondition(t, func() bool {
 		return svc.OutstandingDeliveries() == 0
 	})
 	got := map[string]string{}
 	for line := range strings.Lines(logs.String()) {
 		var record struct {
 			Msg      string `json:"msg"`
 			Endpoint string `json:"endpoint"`
 			Error    string `json:"error"`
 		}
 		_ = json.Unmarshal([]byte(line), &record)
 		if record.Msg == "failed to send notification after retries" {
 			got[record.Endpoint] = record.Error
 		}
 	}
 	want := map[string]string{
 		"slack":      "slack notification failed: status 503",
 		"mattermost": "mattermost notification failed: status 503",
 	}
 	if !maps.Equal(got, want) {
 		t.Errorf("logged errors = %v, want %v", got, want)
 	}
 }
 // ── SlackPayload JSON marshaling ──────────────────────────
 func TestSlackPayloadJSON(t *testing.T) {
@@ -32,27 +32,11 @@ func NewRequestForTest(
 // NewTestService creates a Service suitable for unit testing.
 // It discards log output and uses the given transport.
 func NewTestService(transport http.RoundTripper) *Service {
-	return newService(slog.New(slog.DiscardHandler), transport)
+	return &Service{
-}
+		log:       slog.New(slog.DiscardHandler),
-
+		transport: transport,
-// NewTestServiceWithLogger creates a Service that writes to the
+		history:   NewAlertHistory(),
-// given handler, so tests can assert on emitted log records.
+	}
 func NewTestServiceWithLogger(
 	transport http.RoundTripper,
 	handler slog.Handler,
 ) *Service {
 	return newService(slog.New(handler), transport)
 }
 // Drain exports drain for testing.
 func (svc *Service) Drain(ctx context.Context) {
 	svc.drain(ctx)
 }
 // OutstandingDeliveries reports how many delivery goroutines
 // are currently tracked as in flight.
 func (svc *Service) OutstandingDeliveries() int64 {
 	return svc.outstanding.Load()
 }
 // SetNtfyURL sets the ntfy URL on a Service for testing.
@@ -85,11 +69,10 @@ func (svc *Service) SendNtfy(
 func (svc *Service) SendSlack(
 	ctx context.Context,
 	webhookURL *url.URL,
 	failed error,
 	title, message, priority string,
 ) error {
 	return svc.sendSlack(
-		ctx, webhookURL, failed, title, message, priority,
+		ctx, webhookURL, title, message, priority,
 	)
 }
@@ -12,8 +12,6 @@ import (
 	"log/slog"
 	"net/http"
 	"net/url"
 	"sync"
 	"sync/atomic"
 	"time"
 	"go.uber.org/fx"
@@ -117,41 +115,19 @@ type Service struct {
 	history              *AlertHistory
 	retryConfig          RetryConfig
 	sleepFn              func(time.Duration) <-chan time.Time
 	// Shutdown draining state.  drainMu guards draining and
 	// serialises it against the counter increment in
 	// startDelivery; inFlight tracks the delivery goroutines
 	// themselves and outstanding mirrors its count so a timed
 	// out drain can report how many were abandoned.
 	drainMu     sync.Mutex
 	draining    bool
 	inFlight    sync.WaitGroup
 	outstanding atomic.Int64
 	abandon     chan struct{}
 	abandonOnce sync.Once
 }
 // newService builds a Service with the fields every Service
 // needs regardless of how it was constructed.
 func newService(
 	log *slog.Logger,
 	transport http.RoundTripper,
 ) *Service {
 	return &Service{
 		log:       log,
 		transport: transport,
 		history:   NewAlertHistory(),
 		abandon:   make(chan struct{}),
 	}
 }
 // New creates a new notify Service.
 func New(
-	lifecycle fx.Lifecycle,
+	_ fx.Lifecycle,
 	params Params,
 ) (*Service, error) {
-	svc := newService(params.Logger.Get(), http.DefaultTransport)
+	svc := &Service{
-	svc.config = params.Config
+		log:       params.Logger.Get(),
 		transport: http.DefaultTransport,
 		config:    params.Config,
 		history:   NewAlertHistory(),
 	}
 	if params.Config.NtfyTopic != "" {
 		u, err := ValidateWebhookURL(
@@ -192,14 +168,6 @@ func New(
 		svc.mattermostWebhookURL = u
 	}
 	lifecycle.Append(fx.Hook{
 		OnStop: func(ctx context.Context) error {
 			svc.drain(ctx)
 			return nil
 		},
 	})
 	return svc, nil
 }
@@ -226,32 +194,6 @@ func (svc *Service) SendNotification(
 	svc.dispatchMattermost(ctx, title, message, priority)
 }
 // dispatch delivers a notification to one endpoint on a
 // tracked background goroutine.
 //
 // The delivery context is detached from ctx with
 // context.WithoutCancel so that a cancelled caller does not
 // kill a delivery already under way; the shutdown drain, not
 // the caller, decides how long deliveries may keep running.
 func (svc *Service) dispatch(
 	ctx context.Context,
 	endpoint string,
 	send func(context.Context) error,
 ) {
 	notifyCtx := context.WithoutCancel(ctx)
 	svc.startDelivery(endpoint, func() {
 		err := svc.deliverWithRetry(notifyCtx, endpoint, send)
 		if err != nil {
 			svc.log.Error(
 				"failed to send notification after retries",
 				"endpoint", endpoint,
 				"error", err,
 			)
 		}
 	})
 }
 func (svc *Service) dispatchNtfy(
 	ctx context.Context,
 	title, message, priority string,
@@ -260,11 +202,26 @@ func (svc *Service) dispatchNtfy(
 		return
 	}
-	svc.dispatch(ctx, "ntfy", func(c context.Context) error {
+	go func() {
-		return svc.sendNtfy(
+		notifyCtx := context.WithoutCancel(ctx)
-			c, svc.ntfyURL, title, message, priority,
+
 		err := svc.deliverWithRetry(
 			notifyCtx, "ntfy",
 			func(c context.Context) error {
 				return svc.sendNtfy(
 					c, svc.ntfyURL,
 					title, message, priority,
 				)
 			},
 		)
-	})
+		if err != nil {
 			svc.log.Error(
 				"failed to send ntfy notification "+
 					"after retries",
 				"error", err,
 			)
 		}
 	}()
 }
 func (svc *Service) dispatchSlack(
@@ -275,12 +232,26 @@ func (svc *Service) dispatchSlack(
 		return
 	}
-	svc.dispatch(ctx, "slack", func(c context.Context) error {
+	go func() {
-		return svc.sendSlack(
+		notifyCtx := context.WithoutCancel(ctx)
-			c, svc.slackWebhookURL, ErrSlackFailed,
+
-			title, message, priority,
+		err := svc.deliverWithRetry(
 			notifyCtx, "slack",
 			func(c context.Context) error {
 				return svc.sendSlack(
 					c, svc.slackWebhookURL,
 					title, message, priority,
 				)
 			},
 		)
-	})
+		if err != nil {
 			svc.log.Error(
 				"failed to send slack notification "+
 					"after retries",
 				"error", err,
 			)
 		}
 	}()
 }
 func (svc *Service) dispatchMattermost(
@@ -291,15 +262,26 @@ func (svc *Service) dispatchMattermost(
 		return
 	}
-	svc.dispatch(
+	go func() {
-		ctx, "mattermost",
+		notifyCtx := context.WithoutCancel(ctx)
-		func(c context.Context) error {
+
-			return svc.sendSlack(
+		err := svc.deliverWithRetry(
-				c, svc.mattermostWebhookURL, ErrMattermostFailed,
+			notifyCtx, "mattermost",
-				title, message, priority,
+			func(c context.Context) error {
 				return svc.sendSlack(
 					c, svc.mattermostWebhookURL,
 					title, message, priority,
 				)
 			},
 		)
 		if err != nil {
 			svc.log.Error(
 				"failed to send mattermost notification "+
 					"after retries",
 				"error", err,
 			)
-		},
+		}
-	)
+	}()
 }
 func (svc *Service) sendNtfy(
@@ -371,14 +353,9 @@ type SlackAttachment struct {
 	Text  string `json:"text"`
 }
 // sendSlack posts to a Slack or Mattermost incoming webhook, which
 // take the same payload. An HTTP error status is returned wrapped in
 // failed, ErrSlackFailed or ErrMattermostFailed, so the error names
 // the endpoint.
 func (svc *Service) sendSlack(
 	ctx context.Context,
 	webhookURL *url.URL,
 	failed error,
 	title, message, priority string,
 ) error {
 	ctx, cancel := context.WithTimeout(
@@ -426,7 +403,7 @@ func (svc *Service) sendSlack(
 	if resp.StatusCode >= httpStatusClientError {
 		return fmt.Errorf(
 			"%w: status %d",
-			failed, resp.StatusCode,
+			ErrSlackFailed, resp.StatusCode,
 		)
 	}
@@ -2,7 +2,6 @@ package notify
 import (
 	"context"
 	"fmt"
 	"math"
 	"math/rand/v2"
 	"time"
@@ -115,23 +114,13 @@ func (svc *Service) deliverWithRetry(
 			"endpoint", endpoint,
 			"attempt", attempt+1,
 			"maxAttempts", cfg.MaxRetries+1,
-			// As text: the JSON log writes a time.Duration as
+			"retryIn", delay,
 			// bare nanoseconds.
 			"retryIn", delay.String(),
 			"error", lastErr,
 		)
 		select {
 		case <-ctx.Done():
 			return ctx.Err()
 		case <-svc.abandon:
 			// Shutdown drained past its deadline; stop
 			// sleeping rather than outlive the process.
 			// A nil channel (Service built without a
 			// constructor) simply never fires.
 			return fmt.Errorf(
 				"%w: %s", ErrDeliveryAbandoned, endpoint,
 			)
 		case <-svc.sleepFunc(delay):
 		}
 	}
@@ -2,7 +2,6 @@ package notify_test
 import (
 	"context"
 	"encoding/json"
 	"errors"
 	"net/http"
 	"net/http/httptest"
@@ -190,50 +189,6 @@ func TestDeliverWithRetryExhaustsAttempts(t *testing.T) {
 	}
 }
 // TestDeliverWithRetryLogsRetryInAsText checks that the wait
 // before a retry is logged as text such as "1.02s", not as a
 // count of nanoseconds.
 func TestDeliverWithRetryLogsRetryInAsText(t *testing.T) {
 	t.Parallel()
 	svc, logs := newLoggingService(http.DefaultTransport)
 	svc.SetRetryConfig(notify.RetryConfig{
 		MaxRetries: 1,
 		BaseDelay:  time.Second,
 		MaxDelay:   time.Second,
 	})
 	var waited time.Duration
 	svc.SetSleepFunc(func(d time.Duration) <-chan time.Time {
 		waited = d
 		return instantSleep(d)
 	})
 	_ = svc.DeliverWithRetry(
 		context.Background(), "test",
 		func(_ context.Context) error {
 			return errFail
 		},
 	)
 	// With one retry, only the first failure is logged.
 	var record map[string]any
 	err := json.Unmarshal([]byte(logs.String()), &record)
 	if err != nil {
 		t.Fatalf("log is not one JSON record: %v\n%s", err, logs)
 	}
 	if record["retryIn"] != waited.String() {
 		t.Errorf(
 			"retryIn logged as %v, want %q",
 			record["retryIn"], waited.String(),
 		)
 	}
 }
 func TestDeliverWithRetryRespectsContextCancellation(
 	t *testing.T,
 ) {
@@ -1,119 +0,0 @@
 package notify
 import (
 	"context"
 	"errors"
 )
 // ErrDeliveryAbandoned is returned by a retry loop that was
 // cut short because shutdown drained past its deadline.
 var ErrDeliveryAbandoned = errors.New(
 	"notification delivery abandoned at shutdown",
 )
 // startDelivery runs fn on its own goroutine while tracking it,
 // so that drain can wait for it during shutdown.
 //
 // The WaitGroup counter is incremented here, on the caller's
 // goroutine, before the worker exists: incrementing it inside
 // the worker would race with drain's Wait and could let
 // shutdown sail past a delivery that had not started yet.
 //
 // Once draining has begun the delivery is refused outright
 // rather than queued, so a steady stream of newly submitted
 // notifications cannot keep extending the drain.
 func (svc *Service) startDelivery(endpoint string, fn func()) {
 	svc.drainMu.Lock()
 	if svc.draining {
 		svc.drainMu.Unlock()
 		svc.log.Warn(
 			"notification not dispatched: shutdown in progress",
 			"endpoint", endpoint,
 		)
 		return
 	}
 	svc.outstanding.Add(1)
 	// WaitGroup.Go increments the counter synchronously, here,
 	// and only then starts the goroutine.
 	svc.inFlight.Go(func() {
 		// Runs before the WaitGroup counter is decremented, so
 		// a drain that times out reports an accurate count.
 		defer svc.outstanding.Add(-1)
 		fn()
 	})
 	svc.drainMu.Unlock()
 }
 // drain waits for in-flight notification deliveries to finish.
 //
 // It first stops accepting new deliveries, then waits until
 // either every outstanding delivery has completed or ctx
 // expires — whichever comes first.  ctx is the context fx
 // passes to the OnStop hook, so a permanently dead webhook
 // cannot hang shutdown indefinitely.
 //
 // When the deadline arrives with deliveries still outstanding,
 // the count is logged at warn level and the abandon channel is
 // closed, which releases any retry loop sleeping in backoff.
 // Deliveries already inside an HTTP round trip are bounded by
 // the existing httpClientTimeout instead.
 //
 // A ctx that is already expired on entry is not by itself cause
 // for alarm: if nothing is outstanding there is nothing to
 // abandon, and the drain says so at debug level rather than
 // warning about deliveries that do not exist.
 func (svc *Service) drain(ctx context.Context) {
 	svc.drainMu.Lock()
 	svc.draining = true
 	svc.drainMu.Unlock()
 	done := make(chan struct{})
 	go func() {
 		svc.inFlight.Wait()
 		close(done)
 	}()
 	select {
 	case <-done:
 		svc.log.Debug(
 			"all in-flight notifications completed",
 		)
 	case <-ctx.Done():
 		// outstanding is decremented before the WaitGroup
 		// counter, and startDelivery can no longer add to it
 		// now that draining is set, so a zero here means every
 		// delivery really did finish.  ctx expiring in that
 		// state (an OnStop context that was already cancelled
 		// on entry is the usual way) abandons nothing, so it
 		// must not close abandon or warn about it.
 		abandoned := svc.outstanding.Load()
 		if abandoned == 0 {
 			svc.log.Debug(
 				"all in-flight notifications completed",
 			)
 			return
 		}
 		svc.abandonOnce.Do(func() {
 			if svc.abandon != nil {
 				close(svc.abandon)
 			}
 		})
 		svc.log.Warn(
 			"shutdown deadline reached with notifications "+
 				"still in flight; abandoning them",
 			"abandoned", abandoned,
 			"error", ctx.Err(),
 		)
 	}
 }
@@ -1,593 +0,0 @@
 package notify_test
 import (
 	"bytes"
 	"context"
 	"log/slog"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
 	"strings"
 	"sync"
 	"sync/atomic"
 	"testing"
 	"time"
 	"go.uber.org/fx"
 	"sneak.berlin/go/dnswatcher/internal/config"
 	"sneak.berlin/go/dnswatcher/internal/globals"
 	"sneak.berlin/go/dnswatcher/internal/logger"
 	"sneak.berlin/go/dnswatcher/internal/notify"
 )
 // Timings used by the drain tests.  They stay in the same
 // 10-100ms band as the retry tests so the suite never waits on
 // a real backoff delay.
 const (
 	// inFlightHold is how long a delivery is kept mid-request
 	// before the handler is released.
 	inFlightHold = 30 * time.Millisecond
 	// drainDeadline bounds a drain that is expected to time
 	// out.
 	drainDeadline = 50 * time.Millisecond
 	// timeoutDrainBound is how long a drain given drainDeadline
 	// may take to return before the test gives up on it.  At
 	// forty times drainDeadline it leaves ample room for
 	// scheduling delay on a loaded box under -race, yet it is far
 	// below the test binary's -timeout, so a drain that its
 	// deadline does not bound fails that one test instead of
 	// hanging the package.
 	timeoutDrainBound = 2 * time.Second
 	// longDrainDeadline is the deadline given to a drain that is
 	// expected to finish well before it: when the in-flight
 	// delivery completes after inFlightHold, or at once when
 	// nothing is in flight.  It is far above inFlightHold, so
 	// those drains never reach it, and four times
 	// idleDrainBound, so an idle drain that waited for its
 	// deadline instead of returning fails that bound.
 	longDrainDeadline = 2 * time.Second
 	// reachEndpointTimeout is how long a submitted delivery may
 	// take to reach the test server.  That normally takes a few
 	// milliseconds; the margin is for a loaded box under -race,
 	// and only a failing run ever waits this long.
 	reachEndpointTimeout = 2 * time.Second
 	// settleDelay is how long to wait before asserting that
 	// something did *not* happen.
 	settleDelay = 50 * time.Millisecond
 	// idleDrainBound is the upper bound on a drain that has
 	// nothing in flight.  It is deliberately far above the cost
 	// of the goroutine hop through inFlight.Wait() — which
 	// reached 57ms on a loaded box under -race with the package's
 	// parallel tests — and far below longDrainDeadline, the
 	// deadline such a drain is given.  A drain that blocked until
 	// its deadline instead of returning on the WaitGroup
 	// therefore still fails this bound, but scheduling delay
 	// alone cannot.
 	idleDrainBound = 500 * time.Millisecond
 )
 // syncBuffer is an io.Writer safe for concurrent use, so log
 // output written from delivery goroutines can be inspected.
 type syncBuffer struct {
 	mu  sync.Mutex
 	buf bytes.Buffer
 }
 func (sb *syncBuffer) Write(p []byte) (int, error) {
 	sb.mu.Lock()
 	defer sb.mu.Unlock()
 	return sb.buf.Write(p) //nolint:wrapcheck // test helper
 }
 func (sb *syncBuffer) String() string {
 	sb.mu.Lock()
 	defer sb.mu.Unlock()
 	return sb.buf.String()
 }
 // newLoggingService returns a Service writing JSON logs into
 // the returned buffer, debug level included.
 func newLoggingService(
 	transport http.RoundTripper,
 ) (*notify.Service, *syncBuffer) {
 	logs := &syncBuffer{}
 	handler := slog.NewJSONHandler(
 		logs, &slog.HandlerOptions{Level: slog.LevelDebug},
 	)
 	return notify.NewTestServiceWithLogger(transport, handler),
 		logs
 }
 // blockingNtfyServer returns a server whose handler signals on
 // entered, waits for release, and then responds 200.
 func blockingNtfyServer(
 	entered chan<- struct{},
 	release <-chan struct{},
 	served *atomic.Bool,
 ) *httptest.Server {
 	var once sync.Once
 	return httptest.NewServer(
 		http.HandlerFunc(
 			func(w http.ResponseWriter, _ *http.Request) {
 				once.Do(func() { close(entered) })
 				<-release
 				served.Store(true)
 				w.WriteHeader(http.StatusOK)
 			}),
 	)
 }
 // TestDrainWaitsForInFlightDelivery verifies that a delivery
 // already under way when shutdown starts is allowed to finish.
 func TestDrainWaitsForInFlightDelivery(t *testing.T) {
 	t.Parallel()
 	var served atomic.Bool
 	entered := make(chan struct{})
 	release := make(chan struct{})
 	srv := blockingNtfyServer(entered, release, &served)
 	defer srv.Close()
 	// srv.Close waits for the handler, so release it however the
 	// test ends; otherwise a drain that returns early hangs the
 	// package instead of failing this test.
 	releaseHandler := sync.OnceFunc(func() { close(release) })
 	defer releaseHandler()
 	topicURL, _ := url.Parse(srv.URL)
 	svc := notify.NewTestService(http.DefaultTransport)
 	svc.SetNtfyURL(topicURL)
 	svc.SendNotification(
 		context.Background(), "t", "m", prioInfo,
 	)
 	// Make sure the delivery really is mid-request before the
 	// drain begins.
 	select {
 	case <-entered:
 	case <-time.After(reachEndpointTimeout):
 		t.Fatal("delivery never reached the endpoint")
 	}
 	// As in TestDrainBoundedByContextDeadline: start is captured
 	// before the clock it is compared against, here the timer
 	// holding the delivery open, so elapsed covers the whole hold
 	// and the lower bound cannot come out short from scheduling
 	// delay alone.
 	start := time.Now()
 	timer := time.AfterFunc(inFlightHold, releaseHandler)
 	defer timer.Stop()
 	ctx, cancel := context.WithTimeout(
 		context.Background(), longDrainDeadline,
 	)
 	defer cancel()
 	svc.Drain(ctx)
 	elapsed := time.Since(start)
 	if !served.Load() {
 		t.Error(
 			"drain returned before the in-flight delivery " +
 				"completed",
 		)
 	}
 	if elapsed < inFlightHold {
 		t.Errorf(
 			"drain took %v, want at least %v",
 			elapsed, inFlightHold,
 		)
 	}
 	if got := svc.OutstandingDeliveries(); got != 0 {
 		t.Errorf("outstanding deliveries = %d, want 0", got)
 	}
 }
 // neverFires returns a channel that never delivers, standing in
 // for a long backoff sleep without actually sleeping.
 func neverFires(_ time.Duration) <-chan time.Time {
 	return make(chan time.Time)
 }
 // TestDrainBoundedByContextDeadline verifies that a delivery
 // stuck retrying against a dead endpoint does not hold shutdown
 // past the OnStop context deadline, and that the abandoned
 // deliveries are logged at warn level rather than dropped
 // silently.
 func TestDrainBoundedByContextDeadline(t *testing.T) {
 	t.Parallel()
 	var requests atomic.Int64
 	srv := httptest.NewServer(
 		http.HandlerFunc(
 			func(w http.ResponseWriter, _ *http.Request) {
 				requests.Add(1)
 				w.WriteHeader(http.StatusInternalServerError)
 			}),
 	)
 	defer srv.Close()
 	topicURL, _ := url.Parse(srv.URL)
 	svc, logs := newLoggingService(http.DefaultTransport)
 	svc.SetNtfyURL(topicURL)
 	// Never let the backoff sleep complete: the delivery is
 	// parked in its retry wait until shutdown releases it.
 	svc.SetSleepFunc(neverFires)
 	svc.SetRetryConfig(notify.RetryConfig{
 		MaxRetries: 5,
 		BaseDelay:  time.Hour,
 		MaxDelay:   time.Hour,
 	})
 	svc.SendNotification(
 		context.Background(), "t", "m", prioError,
 	)
 	waitForCondition(t, func() bool {
 		return requests.Load() >= 1 &&
 			svc.OutstandingDeliveries() == 1
 	})
 	// start must be captured *before* the deadline clock starts,
 	// so that the measured interval is a superset of the deadline
 	// interval.  Capturing it after context.WithTimeout would
 	// make elapsed structurally smaller than drainDeadline and
 	// the lower bound below unfalsifiable-by-luck: it would fail
 	// whenever the two statements were separated by any
 	// scheduling delay, and pass otherwise, regardless of what
 	// the drain did.
 	start := time.Now()
 	ctx, cancel := context.WithTimeout(
 		context.Background(), drainDeadline,
 	)
 	defer cancel()
 	// The upper bound is enforced by a watchdog rather than by
 	// measuring after the fact: a drain that is not bounded at
 	// all never returns here (the delivery is parked in a backoff
 	// that never fires), so an unbounded drain must fail this
 	// test promptly instead of hanging the package until the test
 	// binary's -timeout.
 	returned := make(chan struct{})
 	go func() {
 		defer close(returned)
 		svc.Drain(ctx)
 	}()
 	select {
 	case <-returned:
 	case <-time.After(timeoutDrainBound):
 		t.Fatalf(
 			"drain did not return within %v; its %v deadline "+
 				"did not bound it",
 			timeoutDrainBound, drainDeadline,
 		)
 	}
 	// The lower bound is the real assertion: the drain must have
 	// waited for its whole deadline rather than giving up on the
 	// outstanding delivery early.  With start captured above, an
 	// early return is the only thing that can make it fail.
 	if elapsed := time.Since(start); elapsed < drainDeadline {
 		t.Errorf(
 			"drain returned after %v, before its %v deadline",
 			elapsed, drainDeadline,
 		)
 	}
 	assertAbandonLogged(t, logs.String())
 	// The abandoned delivery must stop retrying rather than
 	// outlive the drain.
 	waitForCondition(t, func() bool {
 		return svc.OutstandingDeliveries() == 0
 	})
 }
 // assertAbandonLogged checks that the drain logged the
 // abandoned deliveries at warn level with a count.
 func assertAbandonLogged(t *testing.T, output string) {
 	t.Helper()
 	if !strings.Contains(output, `"level":"WARN"`) {
 		t.Errorf(
 			"abandoned deliveries not logged at warn level; "+
 				"log output: %s",
 			output,
 		)
 	}
 	if !strings.Contains(output, `"abandoned":1`) {
 		t.Errorf(
 			"abandoned delivery count not logged; "+
 				"log output: %s",
 			output,
 		)
 	}
 }
 // TestDrainRefusesNewDeliveries verifies that notifications
 // submitted after the drain has begun are refused and logged,
 // so a stream of new work cannot extend shutdown indefinitely.
 func TestDrainRefusesNewDeliveries(t *testing.T) {
 	t.Parallel()
 	var requests atomic.Int64
 	srv := httptest.NewServer(
 		http.HandlerFunc(
 			func(w http.ResponseWriter, _ *http.Request) {
 				requests.Add(1)
 				w.WriteHeader(http.StatusOK)
 			}),
 	)
 	defer srv.Close()
 	target, _ := url.Parse(srv.URL)
 	svc, logs := newLoggingService(http.DefaultTransport)
 	svc.SetNtfyURL(target)
 	svc.SetSlackWebhookURL(target)
 	svc.SetMattermostWebhookURL(target)
 	ctx, cancel := context.WithTimeout(
 		context.Background(), longDrainDeadline,
 	)
 	defer cancel()
 	// Nothing is in flight, so this returns immediately and
 	// leaves the service refusing further deliveries.
 	svc.Drain(ctx)
 	for range 3 {
 		svc.SendNotification(
 			context.Background(), "t", "m", prioInfo,
 		)
 	}
 	time.Sleep(settleDelay)
 	if got := requests.Load(); got != 0 {
 		t.Errorf(
 			"%d requests reached the endpoint after drain, "+
 				"want 0",
 			got,
 		)
 	}
 	if got := svc.OutstandingDeliveries(); got != 0 {
 		t.Errorf("outstanding deliveries = %d, want 0", got)
 	}
 	output := logs.String()
 	if !strings.Contains(output, "shutdown in progress") {
 		t.Errorf(
 			"refused deliveries not logged; log output: %s",
 			output,
 		)
 	}
 }
 // recordingLifecycle is a minimal fx.Lifecycle that records the
 // hooks appended to it, so the wiring done by notify.New can be
 // inspected without standing up a whole fx application.
 type recordingLifecycle struct {
 	hooks []fx.Hook
 }
 func (l *recordingLifecycle) Append(hook fx.Hook) {
 	l.hooks = append(l.hooks, hook)
 }
 // newNotifyService builds a Service through the real
 // constructor, wired to the given lifecycle.
 func newNotifyService(
 	t *testing.T,
 	lifecycle fx.Lifecycle,
 	ntfyTopic string,
 ) *notify.Service {
 	t.Helper()
 	g, err := globals.New(nil)
 	if err != nil {
 		t.Fatalf("globals.New: %v", err)
 	}
 	log, err := logger.New(nil, logger.Params{Globals: g})
 	if err != nil {
 		t.Fatalf("logger.New: %v", err)
 	}
 	svc, err := notify.New(lifecycle, notify.Params{
 		Logger: log,
 		Config: &config.Config{NtfyTopic: ntfyTopic},
 	})
 	if err != nil {
 		t.Fatalf("notify.New: %v", err)
 	}
 	return svc
 }
 // TestNewRegistersDrainingStopHook verifies that notify.New
 // wires an OnStop hook into the fx lifecycle and that the hook
 // waits for in-flight deliveries.
 func TestNewRegistersDrainingStopHook(t *testing.T) {
 	t.Parallel()
 	var served atomic.Bool
 	entered := make(chan struct{})
 	release := make(chan struct{})
 	srv := blockingNtfyServer(entered, release, &served)
 	defer srv.Close()
 	// As in TestDrainWaitsForInFlightDelivery: release the handler
 	// however the test ends, before srv.Close waits for it.
 	releaseHandler := sync.OnceFunc(func() { close(release) })
 	defer releaseHandler()
 	lifecycle := &recordingLifecycle{}
 	svc := newNotifyService(t, lifecycle, srv.URL)
 	if len(lifecycle.hooks) != 1 {
 		t.Fatalf(
 			"appended %d lifecycle hooks, want 1",
 			len(lifecycle.hooks),
 		)
 	}
 	stop := lifecycle.hooks[0].OnStop
 	if stop == nil {
 		t.Fatal("lifecycle hook has no OnStop function")
 	}
 	svc.SendNotification(
 		context.Background(), "t", "m", prioInfo,
 	)
 	select {
 	case <-entered:
 	case <-time.After(reachEndpointTimeout):
 		t.Fatal("delivery never reached the endpoint")
 	}
 	timer := time.AfterFunc(inFlightHold, releaseHandler)
 	defer timer.Stop()
 	ctx, cancel := context.WithTimeout(
 		context.Background(), longDrainDeadline,
 	)
 	defer cancel()
 	err := stop(ctx)
 	if err != nil {
 		t.Fatalf("OnStop returned error: %v", err)
 	}
 	if !served.Load() {
 		t.Error(
 			"OnStop returned before the in-flight delivery " +
 				"completed",
 		)
 	}
 }
 // TestDrainWithoutDeliveriesReturnsImmediately verifies the
 // common case: nothing in flight, shutdown is not delayed.
 func TestDrainWithoutDeliveriesReturnsImmediately(t *testing.T) {
 	t.Parallel()
 	svc := notify.NewTestService(http.DefaultTransport)
 	// Captured before the deadline clock, as elsewhere in this
 	// file; for an upper bound that is the conservative
 	// direction, since the measured interval can then only be
 	// longer than the drain itself.
 	start := time.Now()
 	ctx, cancel := context.WithTimeout(
 		context.Background(), longDrainDeadline,
 	)
 	defer cancel()
 	svc.Drain(ctx)
 	if elapsed := time.Since(start); elapsed > idleDrainBound {
 		t.Errorf(
 			"drain of an idle service took %v, want at most "+
 				"%v; its deadline was %v",
 			elapsed, idleDrainBound, longDrainDeadline,
 		)
 	}
 }
 // TestDrainWithCancelledContextDoesNotWarn verifies that an
 // OnStop context that is already dead on entry does not produce
 // an "abandoning them" warning when there was nothing in flight
 // to abandon, and that the drain returns and says at debug level
 // that nothing was in flight.  The expired context wins the
 // select immediately, so only the outstanding count can tell the
 // difference between a genuine timeout and a shutdown that had
 // simply already run out of time with no work left.
 func TestDrainWithCancelledContextDoesNotWarn(t *testing.T) {
 	t.Parallel()
 	svc, logs := newLoggingService(http.DefaultTransport)
 	ctx, cancel := context.WithCancel(context.Background())
 	cancel()
 	// A watchdog, as in TestDrainBoundedByContextDeadline, so
 	// that a drain which never returns fails here instead of
 	// hanging the package.
 	returned := make(chan struct{})
 	go func() {
 		defer close(returned)
 		svc.Drain(ctx)
 	}()
 	select {
 	case <-returned:
 	case <-time.After(idleDrainBound):
 		t.Fatalf(
 			"drain with nothing in flight and a cancelled "+
 				"context did not return within %v",
 			idleDrainBound,
 		)
 	}
 	output := logs.String()
 	// The absence of a warning alone would also pass if the drain
 	// logged nothing at all, so require the debug line it writes
 	// when it finds nothing outstanding.
 	if !strings.Contains(
 		output, "all in-flight notifications completed",
 	) {
 		t.Errorf(
 			"drain did not log that nothing was in flight; "+
 				"log output: %s",
 			output,
 		)
 	}
 	if strings.Contains(output, `"level":"WARN"`) {
 		t.Errorf(
 			"drain with nothing in flight warned about "+
 				"abandoned deliveries; log output: %s",
 			output,
 		)
 	}
 }
@@ -193,9 +193,7 @@ func (c *Checker) checkConnection(
 	c.log.Debug(
 		"port check succeeded",
 		"target", target,
-		// As text: the JSON log writes a time.Duration as bare
+		"latency", latency,
 		// nanoseconds.
 		"latency", latency.String(),
 	)
 	return &PortResult{
@@ -7,8 +7,8 @@ import (
 	"github.com/miekg/dns"
 )
-// DNSClient sends one DNS message to a nameserver and returns the
+// DNSClient abstracts DNS wire-protocol exchanges so the resolver
-// reply. The resolver holds one for UDP and one for TCP.
+// can be tested without hitting real nameservers.
 type DNSClient interface {
 	ExchangeContext(
 		ctx context.Context,
@@ -10,29 +10,6 @@ var (
 		"no authoritative nameservers found",
 	)
 	// ErrNoNameserverAnswered is returned when every nameserver
 	// asked about a name timed out, failed or returned a referral,
 	// so whether the name has addresses is unknown.
 	ErrNoNameserverAnswered = errors.New("no nameserver answered")
 	// ErrUnusableReply is returned when a server replied with an
 	// error such as SERVFAIL, or with a referral that leads no
 	// closer to the name asked about.
 	ErrUnusableReply = errors.New(
 		"reply is an error or a referral that leads no closer",
 	)
 	// ErrTruncated is the reason given for a reply too large for UDP
 	// whose retry over TCP failed.
 	ErrTruncated = errors.New(
 		"reply truncated and its retry over TCP failed",
 	)
 	// ErrIntercepted is returned when every root server refused a
 	// query. Root servers refuse no query, so the refusals came from
 	// something on the network answering in their place.
 	ErrIntercepted = errors.New("this network intercepts DNS queries")
 	// ErrCNAMEDepthExceeded is returned when a CNAME chain
 	// exceeds MaxCNAMEDepth.
 	ErrCNAMEDepthExceeded = errors.New(
@@ -1,81 +0,0 @@
 package resolver
 import (
 	"context"
 	"log/slog"
 	"time"
 	"github.com/miekg/dns"
 )
 // NewWithFailingTCP returns a Resolver whose TCP client gives up before
 // it can connect, so the retry over TCP of every truncated reply fails.
 func NewWithFailingTCP(log *slog.Logger) *Resolver {
 	r := NewFromLogger(log)
 	r.tcp = &tcpClient{timeout: time.Nanosecond}
 	return r
 }
 // ExtractRecordValue exports extractRecordValue for testing.
 func ExtractRecordValue(rr dns.RR) string {
 	return extractRecordValue(rr)
 }
 // UsableReply exports usableReply for testing.
 func UsableReply(resp *dns.Msg, zone string, name string) bool {
 	return usableReply(resp, zone, name)
 }
 // NSSetFrom exports nsSetFrom for testing.
 func NSSetFrom(resp *dns.Msg, domain string) []string {
 	return nsSetFrom(resp, domain)
 }
 // CollectIPs exports collectIPs for testing.
 func CollectIPs(
 	results map[string]*NameserverResponse,
 ) ([]string, string, error) {
 	return collectIPs(results)
 }
 // QueryServers exports queryServers for testing.
 func (r *Resolver) QueryServers(
 	ctx context.Context,
 	servers []string,
 	zone string,
 	name string,
 	qtype uint16,
 ) (*dns.Msg, error) {
 	return r.queryServers(ctx, servers, zone, name, qtype)
 }
 // QueryEachNS exports queryEachNS for testing.
 func (r *Resolver) QueryEachNS(
 	ctx context.Context,
 	nameservers []string,
 	hostname string,
 ) (map[string]*NameserverResponse, error) {
 	return r.queryEachNS(ctx, nameservers, hostname, recordTypes())
 }
 // ResolveNSIPs exports resolveNSIPs for testing.
 func (r *Resolver) ResolveNSIPs(
 	ctx context.Context,
 	nsNames []string,
 ) []string {
 	return r.resolveNSIPs(ctx, nsNames)
 }
 // RootServerList exports rootServerList for testing.
 func RootServerList() []string {
 	return rootServerList()
 }
 // Shuffled exports shuffled for testing.
 func Shuffled(
 	servers []string,
 	shuffle func(n int, swap func(i, j int)),
 ) []string {
 	return shuffled(servers, shuffle)
 }
@@ -4,9 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
 	"math/rand/v2"
 	"net"
 	"slices"
 	"sort"
 	"strings"
 	"time"
@@ -19,6 +17,7 @@ const (
 	maxRetries           = 2
 	maxDelegation        = 20
 	timeoutMultiplier    = 2
 	minDomainLabels      = 2
 )
 // ErrRefused is returned when a DNS server refuses a query.
@@ -89,9 +88,6 @@ func (r *Resolver) tryExchange(
 	return resp, err
 }
 // retryTCP returns the reply to msg over TCP when resp, its reply over
 // UDP, is truncated. When that fails it returns resp, still truncated,
 // which holds only the records that fit.
 func (r *Resolver) retryTCP(
 	ctx context.Context,
 	msg *dns.Msg,
@@ -110,8 +106,9 @@ func (r *Resolver) retryTCP(
 	return resp
 }
-// queryDNS sends a DNS query to a specific server IP, never asking it
+// queryDNS sends a DNS query to a specific server IP.
-// for recursion. A reply of REFUSED is returned as ErrRefused.
+// Tries non-recursive first, falls back to recursive on
 // REFUSED (handles DNS interception environments).
 func (r *Resolver) queryDNS(
 	ctx context.Context,
 	serverIP string,
@@ -135,12 +132,25 @@ func (r *Resolver) queryDNS(
 	}
 	if resp.Rcode == dns.RcodeRefused {
-		return nil, fmt.Errorf(
+		msg.RecursionDesired = true
-			"query %s @%s: %w", name, serverIP, ErrRefused,
+
-		)
+		resp, err = r.tryExchange(ctx, msg, addr)
 		if err != nil {
 			return nil, fmt.Errorf(
 				"query %s @%s: %w", name, serverIP, err,
 			)
 		}
 		if resp.Rcode == dns.RcodeRefused {
 			return nil, fmt.Errorf(
 				"query %s @%s: %w", name, serverIP, ErrRefused,
 			)
 		}
 	}
-	return r.retryTCP(ctx, msg, addr, resp), nil
+	resp = r.retryTCP(ctx, msg, addr, resp)
 	return resp, nil
 }
 func extractNSSet(rrs []dns.RR) []string {
@@ -198,33 +208,21 @@ func (r *Resolver) followDelegation(
 	domain string,
 	servers []string,
 ) ([]string, error) {
 	// servers are the root servers, the servers of zone ".".
 	zone := "."
 	for range maxDelegation {
 		if checkCtx(ctx) != nil {
 			return nil, ErrContextCanceled
 		}
 		resp, err := r.queryServers(
-			ctx, servers, zone, domain, dns.TypeNS,
+			ctx, servers, domain, dns.TypeNS,
 		)
 		if err != nil {
 			return nil, err
 		}
-		nsSet := nsSetFrom(resp, domain)
+		ansNS := extractNSSet(resp.Answer)
-		if len(nsSet) > 0 {
+		if len(ansNS) > 0 {
-			return nsSet, nil
+			return ansNS, nil
 		}
 		// An authoritative reply comes from the servers of the zone
 		// domain is in; it is not a referral, even when its authority
 		// section lists that zone's NS records. Without NS records in
 		// the answer, domain is not the zone's apex and has no
 		// nameservers of its own.
 		if resp.Authoritative {
 			return nil, ErrNoNameservers
 		}
 		authNS := extractNSSet(resp.Ns)
@@ -244,135 +242,35 @@ func (r *Resolver) followDelegation(
 		}
 		servers = nextServers
 		zone = referralZone(resp)
 	}
 	return nil, ErrNoNameservers
 }
 // shuffled returns a copy of servers in the order shuffle puts them
 // in. The resolver passes rand.Shuffle, so each time it walks a list of
 // servers it starts at a random one, and no one server gets every
 // first query.
 func shuffled(
 	servers []string,
 	shuffle func(n int, swap func(i, j int)),
 ) []string {
 	order := slices.Clone(servers)
 	shuffle(len(order), func(i, j int) {
 		order[i], order[j] = order[j], order[i]
 	})
 	return order
 }
 // queryServers asks servers, the servers of zone, about name in a random
 // order until one gives a usable reply. A server that times out, refuses
 // or gives a reply that is not usable is passed over for the next. When
 // every server refused, the error says so, and when they are the root
 // servers it is ErrIntercepted.
 func (r *Resolver) queryServers(
 	ctx context.Context,
 	servers []string,
 	zone string,
 	name string,
 	qtype uint16,
 ) (*dns.Msg, error) {
 	var lastErr error
-	refused := 0
+	for _, ip := range servers {
 	for _, ip := range shuffled(servers, rand.Shuffle) {
 		if checkCtx(ctx) != nil {
 			return nil, ErrContextCanceled
 		}
 		resp, err := r.queryDNS(ctx, ip, name, qtype)
 		if err == nil && !usableReply(resp, zone, name) {
 			err = fmt.Errorf(
 				"query %s @%s: %w", name, ip, ErrUnusableReply,
 			)
 		}
 		if err == nil {
 			return resp, nil
 		}
 		if errors.Is(err, ErrRefused) {
 			refused++
 		}
 		lastErr = err
 	}
 	if refused == len(servers) && zone == "." {
 		return nil, fmt.Errorf(
 			"every root server refused a query for %s: %w",
 			name, ErrIntercepted,
 		)
 	}
 	if refused == len(servers) {
 		return nil, fmt.Errorf(
 			"every server of %s refused a query for %s: %w",
 			zone, name, ErrRefused,
 		)
 	}
 	return nil, fmt.Errorf("all servers failed: %w", lastErr)
 }
 // usableReply reports whether resp, a reply from one of the servers of
 // zone to a query about name, is usable. An error reply such as SERVFAIL
 // is not. Nor is a referral, unless it refers the query to a zone below
 // zone that name is in: a server that refers it back to zone, up or
 // sideways does not serve zone as it should.
 func usableReply(resp *dns.Msg, zone string, name string) bool {
 	if resp.Rcode != dns.RcodeSuccess && resp.Rcode != dns.RcodeNameError {
 		return false
 	}
 	child := referralZone(resp)
 	if resp.Authoritative || len(resp.Answer) > 0 || child == "" {
 		return true
 	}
 	return child != zone && dns.IsSubDomain(zone, child) &&
 		dns.IsSubDomain(child, name)
 }
 // referralZone returns the zone a referral refers the query to: the
 // owner name of the NS records in resp's authority section, or "" when
 // there are none.
 func referralZone(resp *dns.Msg) string {
 	for _, rr := range resp.Ns {
 		if ns, ok := rr.(*dns.NS); ok {
 			return strings.ToLower(ns.Hdr.Name)
 		}
 	}
 	return ""
 }
 // nsSetFrom returns the NS set of domain that resp, a reply to a query
 // for domain's NS records, gives: the delegation in a referral to domain
 // itself, or else the NS records in the answer; empty when it gives
 // neither. A referral to domain comes from its parent zone's servers,
 // which all hold the same delegation, so the set does not depend on
 // which of them answered. domain's own servers, which can disagree about
 // their NS records, are then not asked.
 func nsSetFrom(resp *dns.Msg, domain string) []string {
 	if referralZone(resp) == domain {
 		return extractNSSet(resp.Ns)
 	}
 	return extractNSSet(resp.Answer)
 }
 // resolveNSIPs returns the addresses of every nameserver in nsNames
 // whose name resolves, for a referral that carries none. The walk can
 // then go on to the zone's other nameservers when one gives no usable
 // reply.
 func (r *Resolver) resolveNSIPs(
 	ctx context.Context,
 	nsNames []string,
@@ -384,6 +282,10 @@ func (r *Resolver) resolveNSIPs(
 		if err == nil {
 			ips = append(ips, resolved...)
 		}
 		if len(ips) > 0 {
 			break
 		}
 	}
 	return ips
@@ -402,7 +304,6 @@ func (r *Resolver) resolveNSIterative(
 	domain = dns.Fqdn(domain)
 	servers := rootServerList()
 	zone := "."
 	for range maxDelegation {
 		if checkCtx(ctx) != nil {
@@ -410,13 +311,13 @@ func (r *Resolver) resolveNSIterative(
 		}
 		resp, err := r.queryServers(
-			ctx, servers, zone, domain, dns.TypeNS,
+			ctx, servers, domain, dns.TypeNS,
 		)
 		if err != nil {
 			return nil, err
 		}
-		nsNames := nsSetFrom(resp, domain)
+		nsNames := extractNSSet(resp.Answer)
 		if len(nsNames) > 0 {
 			return nsNames, nil
 		}
@@ -435,7 +336,6 @@ func (r *Resolver) resolveNSIterative(
 		}
 		servers = nextServers
 		zone = referralZone(resp)
 	}
 	return nil, ErrNoNameservers
@@ -453,7 +353,6 @@ func (r *Resolver) resolveARecord(
 	hostname = dns.Fqdn(hostname)
 	servers := rootServerList()
 	zone := "."
 	for range maxDelegation {
 		if checkCtx(ctx) != nil {
@@ -461,7 +360,7 @@ func (r *Resolver) resolveARecord(
 		}
 		resp, err := r.queryServers(
-			ctx, servers, zone, hostname, dns.TypeA,
+			ctx, servers, hostname, dns.TypeA,
 		)
 		if err != nil {
 			return nil, fmt.Errorf(
@@ -499,7 +398,6 @@ func (r *Resolver) resolveARecord(
 		}
 		servers = nextServers
 		zone = referralZone(resp)
 	}
 	return nil, fmt.Errorf(
@@ -509,10 +407,7 @@ func (r *Resolver) resolveARecord(
 // FindAuthoritativeNameservers traces the delegation chain from
 // root servers to discover all authoritative nameservers for the
-// given domain, as the delegation from its parent zone's servers lists
+// given domain. Walks up the label hierarchy for subdomains.
 // them. For a name that is not a zone apex it tries each
 // parent name in turn, so it returns the nameservers of the zone the
 // name is in.
 func (r *Resolver) FindAuthoritativeNameservers(
 	ctx context.Context,
 	domain string,
@@ -539,49 +434,17 @@ func (r *Resolver) FindAuthoritativeNameservers(
 			return nsNames, nil
 		}
 		// The root servers would refuse every parent name too.
 		if errors.Is(err, ErrIntercepted) {
 			return nil, err
 		}
 	}
 	return nil, ErrNoNameservers
 }
 // recordTypes returns the record types a nameserver is asked for when a
 // name is checked.
 func recordTypes() []uint16 {
 	return []uint16{
 		dns.TypeA, dns.TypeAAAA, dns.TypeCNAME,
 		dns.TypeMX, dns.TypeTXT, dns.TypeSRV,
 		dns.TypeCAA, dns.TypeNS,
 	}
 }
 // addressTypes returns the record types ResolveIPAddresses asks for,
 // the only ones it reads.
 func addressTypes() []uint16 {
 	return []uint16{dns.TypeA, dns.TypeAAAA, dns.TypeCNAME}
 }
 // QueryNameserver queries a specific nameserver for all record
 // types and builds a NameserverResponse.
 func (r *Resolver) QueryNameserver(
 	ctx context.Context,
 	nsHostname string,
 	hostname string,
 ) (*NameserverResponse, error) {
 	return r.queryNameserver(ctx, nsHostname, hostname, recordTypes())
 }
 // queryNameserver queries a specific nameserver for the record types
 // in qtypes and builds a NameserverResponse.
 func (r *Resolver) queryNameserver(
 	ctx context.Context,
 	nsHostname string,
 	hostname string,
 	qtypes []uint16,
 ) (*NameserverResponse, error) {
 	if checkCtx(ctx) != nil {
 		return nil, ErrContextCanceled
@@ -594,7 +457,7 @@ func (r *Resolver) queryNameserver(
 	hostname = dns.Fqdn(hostname)
-	return r.queryTypes(ctx, nsHostname, nsIPs[0], hostname, qtypes)
+	return r.queryAllTypes(ctx, nsHostname, nsIPs[0], hostname)
 }
 // QueryNameserverIP queries a nameserver by its IP address directly,
@@ -611,15 +474,14 @@ func (r *Resolver) QueryNameserverIP(
 	hostname = dns.Fqdn(hostname)
-	return r.queryTypes(ctx, nsHostname, nsIP, hostname, recordTypes())
+	return r.queryAllTypes(ctx, nsHostname, nsIP, hostname)
 }
-func (r *Resolver) queryTypes(
+func (r *Resolver) queryAllTypes(
 	ctx context.Context,
 	nsHostname string,
 	nsIP string,
 	hostname string,
 	qtypes []uint16,
 ) (*NameserverResponse, error) {
 	resp := &NameserverResponse{
 		Nameserver: nsHostname,
@@ -627,6 +489,12 @@ func (r *Resolver) queryTypes(
 		Status:     StatusOK,
 	}
 	qtypes := []uint16{
 		dns.TypeA, dns.TypeAAAA, dns.TypeCNAME,
 		dns.TypeMX, dns.TypeTXT, dns.TypeSRV,
 		dns.TypeCAA, dns.TypeNS,
 	}
 	state := r.queryEachType(ctx, nsIP, hostname, qtypes, resp)
 	classifyResponse(resp, state)
@@ -636,17 +504,10 @@ func (r *Resolver) queryTypes(
 type queryState struct {
 	gotNXDomain bool
 	gotSERVFAIL bool
 	gotRefused  bool
 	gotTimeout  bool
 	gotReferral bool
 	netErr      error
 	hasRecords  bool
 	answered    bool
 }
 // queryEachType asks the nameserver at nsIP about hostname once for each
 // record type in qtypes, and lists in resp.FailedTypes the types whose
 // query got no usable reply, logging each with the reason.
 func (r *Resolver) queryEachType(
 	ctx context.Context,
 	nsIP string,
@@ -661,30 +522,7 @@ func (r *Resolver) queryEachType(
 			break
 		}
-		err := r.querySingleType(ctx, nsIP, hostname, qtype, resp, &state)
+		r.querySingleType(ctx, nsIP, hostname, qtype, resp, &state)
 		if err == nil {
 			state.answered = true
 			continue
 		}
 		rtype := dns.TypeToString[qtype]
 		resp.FailedTypes = append(resp.FailedTypes, rtype)
 		r.log.Warn(
 			"record type query failed",
 			"hostname", hostname,
 			"nameserver", resp.Nameserver,
 			"type", rtype,
 			"error", err,
 		)
 	}
 	// The reply about another type can carry the name's CNAME. When the
 	// query for CNAME itself failed, that is left out too, so Records
 	// holds nothing for a failed type.
 	for _, rtype := range resp.FailedTypes {
 		delete(resp.Records, rtype)
 	}
 	for k := range resp.Records {
@@ -694,9 +532,6 @@ func (r *Resolver) queryEachType(
 	return state
 }
 // querySingleType asks the nameserver at nsIP about hostname's records
 // of type qtype. It returns nil when the nameserver answered: with
 // records, with none, or with NXDOMAIN; otherwise it returns why not.
 func (r *Resolver) querySingleType(
 	ctx context.Context,
 	nsIP string,
@@ -704,57 +539,29 @@ func (r *Resolver) querySingleType(
 	qtype uint16,
 	resp *NameserverResponse,
 	state *queryState,
-) error {
+) {
 	msg, err := r.queryDNS(ctx, nsIP, hostname, qtype)
 	if err != nil {
-		switch {
+		if isTimeout(err) {
 		case isTimeout(err):
 			state.gotTimeout = true
 		case errors.Is(err, ErrRefused):
 			state.gotRefused = true
 		default:
 			state.netErr = err
 		}
-		return err
+		return
 	}
 	if msg.Rcode == dns.RcodeNameError {
 		state.gotNXDomain = true
-		return nil
+		return
 	}
 	if msg.Rcode == dns.RcodeServerFailure {
 		state.gotSERVFAIL = true
-		return fmt.Errorf("server returned SERVFAIL: %w", ErrUnusableReply)
+		return
 	}
 	// A reply with no answer that lists other nameservers, from a server
 	// that does not hold the name's zone, is a referral and says nothing
 	// about the name's records. A server named in the delegation that
 	// does not hold the zone may send one, as do a parent zone's servers
 	// when FindAuthoritativeNameservers found no delegation for the
 	// name's zone and moved on to a parent name.
 	if !msg.Authoritative && len(msg.Answer) == 0 &&
 		len(extractNSSet(msg.Ns)) > 0 {
 		state.gotReferral = true
 		return fmt.Errorf("server returned a referral: %w", ErrUnusableReply)
 	}
 	// A reply still truncated is one whose TCP retry failed, and holds
 	// only the records that fit.
 	if msg.Truncated {
 		state.netErr = ErrTruncated
 		return ErrTruncated
 	}
 	collectAnswerRecords(msg, resp, state)
 	return nil
 }
 func collectAnswerRecords(
@@ -786,37 +593,22 @@ func isTimeout(err error) bool {
 	return false
 }
 // classifyResponse sets the nameserver's status. One that answered no
 // record type has failed, and Error says why; one that answered some has
 // the status of those answers.
 func classifyResponse(resp *NameserverResponse, state queryState) {
 	switch {
 	case state.gotNXDomain && !state.hasRecords:
 		resp.Status = StatusNXDomain
-	case state.gotTimeout && !state.answered:
+	case state.gotTimeout && !state.hasRecords:
 		resp.Status = StatusTimeout
 		resp.Error = "all queries timed out"
-	case state.gotSERVFAIL && !state.answered:
+	case state.gotSERVFAIL && !state.hasRecords:
 		resp.Status = StatusError
 		resp.Error = "server returned SERVFAIL"
 	case state.gotRefused && !state.answered:
 		resp.Status = StatusError
 		resp.Error = "server returned REFUSED"
 	case state.netErr != nil && !state.answered:
 		resp.Status = StatusError
 		resp.Error = "network error: " + state.netErr.Error()
 	case state.gotReferral && !state.answered:
 		resp.Status = StatusError
 		resp.Error = "server returned a referral"
 	case !state.hasRecords && !state.gotNXDomain:
 		resp.Status = StatusNoData
 	}
 }
-// extractRecordValue formats a DNS RR value as a string. DNS names
+// extractRecordValue formats a DNS RR value as a string.
 // are case-insensitive and nameservers may answer in any letter case,
 // so names are lower-cased to compare equal. TXT and CAA values keep
 // their letter case.
 func extractRecordValue(rr dns.RR) string {
 	switch r := rr.(type) {
 	case *dns.A:
@@ -824,29 +616,43 @@ func extractRecordValue(rr dns.RR) string {
 	case *dns.AAAA:
 		return r.AAAA.String()
 	case *dns.CNAME:
-		return strings.ToLower(r.Target)
+		return r.Target
 	case *dns.MX:
-		return fmt.Sprintf("%d %s", r.Preference, strings.ToLower(r.Mx))
+		return fmt.Sprintf("%d %s", r.Preference, r.Mx)
 	case *dns.TXT:
 		return strings.Join(r.Txt, "")
 	case *dns.SRV:
 		return fmt.Sprintf(
 			"%d %d %d %s",
-			r.Priority, r.Weight, r.Port, strings.ToLower(r.Target),
+			r.Priority, r.Weight, r.Port, r.Target,
 		)
 	case *dns.CAA:
 		return fmt.Sprintf(
 			"%d %s \"%s\"", r.Flag, r.Tag, r.Value,
 		)
 	case *dns.NS:
-		return strings.ToLower(r.Ns)
+		return r.Ns
 	default:
 		return ""
 	}
 }
-// QueryAllNameservers discovers the auth NSes of the zone the
+// parentDomain returns the registerable parent domain.
-// hostname is in, then queries each one independently.
+func parentDomain(hostname string) string {
 	hostname = dns.Fqdn(strings.ToLower(hostname))
 	labels := dns.SplitDomainName(hostname)
 	if len(labels) <= minDomainLabels {
 		return strings.Join(labels, ".") + "."
 	}
 	return strings.Join(
 		labels[len(labels)-minDomainLabels:], ".",
 	) + "."
 }
 // QueryAllNameservers discovers auth NSes for the hostname's
 // parent domain, then queries each one independently.
 func (r *Resolver) QueryAllNameservers(
 	ctx context.Context,
 	hostname string,
@@ -855,31 +661,29 @@ func (r *Resolver) QueryAllNameservers(
 		return nil, ErrContextCanceled
 	}
-	nameservers, err := r.FindAuthoritativeNameservers(ctx, hostname)
+	parent := parentDomain(hostname)
 	nameservers, err := r.FindAuthoritativeNameservers(ctx, parent)
 	if err != nil {
 		return nil, err
 	}
-	return r.queryEachNS(ctx, nameservers, hostname, recordTypes())
+	return r.queryEachNS(ctx, nameservers, hostname)
 }
 func (r *Resolver) queryEachNS(
 	ctx context.Context,
 	nameservers []string,
 	hostname string,
 	qtypes []uint16,
 ) (map[string]*NameserverResponse, error) {
 	results := make(map[string]*NameserverResponse)
 	for _, ns := range nameservers {
 		resp, err := r.queryNameserver(ctx, ns, hostname, qtypes)
 		// A query the context cut short says nothing about the
 		// nameserver, so it must not be returned as its failure.
 		if checkCtx(ctx) != nil {
 			return nil, ErrContextCanceled
 		}
 		resp, err := r.QueryNameserver(ctx, ns, hostname)
 		if err != nil {
 			results[ns] = &NameserverResponse{
 				Nameserver: ns,
@@ -907,20 +711,25 @@ func (r *Resolver) LookupNS(
 // LookupAllRecords performs iterative resolution to find all DNS
 // records for the given hostname, keyed by authoritative nameserver.
 // Each nameserver's response carries its status and error with its
 // records.
 func (r *Resolver) LookupAllRecords(
 	ctx context.Context,
 	hostname string,
-) (map[string]*NameserverResponse, error) {
+) (map[string]map[string][]string, error) {
-	return r.QueryAllNameservers(ctx, hostname)
+	results, err := r.QueryAllNameservers(ctx, hostname)
 	if err != nil {
 		return nil, err
 	}
 	out := make(map[string]map[string][]string, len(results))
 	for ns, resp := range results {
 		out[ns] = resp.Records
 	}
 	return out, nil
 }
 // ResolveIPAddresses resolves a hostname to all IPv4 and IPv6
-// addresses, following CNAME chains up to MaxCNAMEDepth. It asks each
+// addresses, following CNAME chains up to MaxCNAMEDepth.
 // nameserver of the name's zone for its A, AAAA and CNAME records only.
 // When no nameserver of the name's zone answered, it returns an error
 // rather than no addresses.
 func (r *Resolver) ResolveIPAddresses(
 	ctx context.Context,
 	hostname string,
@@ -941,20 +750,12 @@ func (r *Resolver) resolveIPWithCNAME(
 		return nil, ErrCNAMEDepthExceeded
 	}
-	nameservers, err := r.FindAuthoritativeNameservers(ctx, hostname)
+	results, err := r.QueryAllNameservers(ctx, hostname)
 	if err != nil {
 		return nil, err
 	}
-	results, err := r.queryEachNS(ctx, nameservers, hostname, addressTypes())
+	ips, cnameTarget := collectIPs(results)
 	if err != nil {
 		return nil, err
 	}
 	ips, cnameTarget, err := collectIPs(results)
 	if err != nil {
 		return nil, fmt.Errorf("resolving %s: %w", hostname, err)
 	}
 	if len(ips) == 0 && cnameTarget != "" {
 		return r.resolveIPWithCNAME(ctx, cnameTarget, depth+1)
@@ -965,31 +766,16 @@ func (r *Resolver) resolveIPWithCNAME(
 	return ips, nil
 }
 // collectIPs returns the addresses in the nameservers' answers and the
 // first CNAME target among them. A nameserver whose query for one of the
 // types failed gave only part of the addresses, and is left out. It
 // returns ErrNoNameserverAnswered when every nameserver timed out,
 // failed, returned a referral or was left out: that is not a name with
 // no addresses.
 func collectIPs(
 	results map[string]*NameserverResponse,
-) ([]string, string, error) {
+) ([]string, string) {
 	seen := make(map[string]bool)
 	var ips []string
 	var cnameTarget string
 	answered := false
 	for _, resp := range results {
 		if resp.Status == StatusTimeout || resp.Status == StatusError ||
 			len(resp.FailedTypes) > 0 {
 			continue
 		}
 		answered = true
 		if resp.Status == StatusNXDomain {
 			continue
 		}
@@ -1013,9 +799,5 @@ func collectIPs(
 		}
 	}
-	if !answered {
+	return ips, cnameTarget
 		return nil, "", ErrNoNameserverAnswered
 	}
 	return ips, cnameTarget, nil
 }
@@ -1,45 +0,0 @@
 package resolver
 import (
 	"testing"
 	"github.com/stretchr/testify/assert"
 )
 // TestClassifyResponse sets a nameserver's status from the results of
 // its queries, built here. One that answered some record types, even
 // with no records, has not failed when its query for another type timed
 // out; one whose every query timed out has.
 func TestClassifyResponse(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name       string
 		results    queryState
 		wantStatus string
 		wantError  string
 	}{
 		{
 			"some types answered with no records, another timed out",
 			queryState{answered: true, gotTimeout: true},
 			StatusNoData, "",
 		},
 		{
 			"every query timed out",
 			queryState{gotTimeout: true},
 			StatusTimeout, "all queries timed out",
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			resp := &NameserverResponse{Status: StatusOK}
 			classifyResponse(resp, tt.results)
 			assert.Equal(t, tt.wantStatus, resp.Status)
 			assert.Equal(t, tt.wantError, resp.Error)
 		})
 	}
 }
@@ -1,285 +0,0 @@
 package resolver_test
 import (
 	"math/rand/v2"
 	"slices"
 	"testing"
 	"github.com/miekg/dns"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"sneak.berlin/go/dnswatcher/internal/resolver"
 )
 // TestCollectIPs_OneAnswerIsEnough checks that one nameserver answering
 // NXDOMAIN says the name has no addresses, though the other timed out.
 func TestCollectIPs_OneAnswerIsEnough(t *testing.T) {
 	t.Parallel()
 	ips, _, err := resolver.CollectIPs(
 		map[string]*resolver.NameserverResponse{
 			"ns1.example.": {Status: resolver.StatusTimeout},
 			"ns2.example.": {Status: resolver.StatusNXDomain},
 		},
 	)
 	require.NoError(t, err)
 	assert.Empty(t, ips)
 }
 // TestCollectIPs_FailedIsNoAnswer checks that nameservers that all have
 // status error, from a refusal, a server failure, a network error or a
 // referral, are no answer rather than a name with no addresses.
 func TestCollectIPs_FailedIsNoAnswer(t *testing.T) {
 	t.Parallel()
 	ips, _, err := resolver.CollectIPs(
 		map[string]*resolver.NameserverResponse{
 			"ns1.example.": {Status: resolver.StatusError},
 			"ns2.example.": {Status: resolver.StatusError},
 		},
 	)
 	require.ErrorIs(t, err, resolver.ErrNoNameserverAnswered)
 	assert.Empty(t, ips)
 }
 // TestCollectIPs_FailedTypeIsNoAnswer checks that a nameserver whose
 // query for one of the types failed is no answer: its addresses are
 // only part of them.
 func TestCollectIPs_FailedTypeIsNoAnswer(t *testing.T) {
 	t.Parallel()
 	ips, _, err := resolver.CollectIPs(
 		map[string]*resolver.NameserverResponse{
 			nsExample1: {
 				Records:     map[string][]string{"A": {"192.0.2.1"}},
 				FailedTypes: []string{"AAAA"},
 				Status:      resolver.StatusOK,
 			},
 		},
 	)
 	require.ErrorIs(t, err, resolver.ErrNoNameserverAnswered)
 	assert.Empty(t, ips)
 }
 const (
 	// exampleCom is the zone most cases of TestUsableReply and
 	// TestNSSetFrom are about, and wwwExampleCom a name in it.
 	exampleCom    = "example.com."
 	wwwExampleCom = "www.example.com."
 	// exampleNS is the server the NS records nsRecord builds name.
 	exampleNS = "ns1.example.net."
 )
 // nsRecord builds an NS record that names a server of zone.
 func nsRecord(zone string) *dns.NS {
 	return &dns.NS{
 		Hdr: dns.RR_Header{
 			Name: zone, Rrtype: dns.TypeNS, Class: dns.ClassINET,
 		},
 		Ns: exampleNS,
 	}
 }
 // referralTo builds a reply that refers the query to the servers of
 // zone.
 func referralTo(zone string) *dns.Msg {
 	msg := new(dns.Msg)
 	msg.Ns = []dns.RR{nsRecord(zone)}
 	return msg
 }
 // TestUsableReply checks which replies from one of a zone's servers are
 // used. A reply that is not usable moves the query on to the zone's
 // next server.
 func TestUsableReply(t *testing.T) {
 	t.Parallel()
 	servfail := new(dns.Msg)
 	servfail.Rcode = dns.RcodeServerFailure
 	answer := new(dns.Msg)
 	answer.Authoritative = true
 	answer.Answer = []dns.RR{nsRecord(exampleCom)}
 	nxdomain := new(dns.Msg)
 	nxdomain.Authoritative = true
 	nxdomain.Rcode = dns.RcodeNameError
 	tests := []struct {
 		name  string
 		resp  *dns.Msg
 		zone  string
 		query string
 		want  bool
 	}{
 		{
 			name: "SERVFAIL", resp: servfail,
 			zone: exampleCom, query: exampleCom, want: false,
 		},
 		{
 			name: "answer", resp: answer,
 			zone: exampleCom, query: exampleCom, want: true,
 		},
 		{
 			name: "NXDOMAIN", resp: nxdomain,
 			zone: ".", query: exampleCom, want: true,
 		},
 		{
 			name: "root refers to com", resp: referralTo("com."),
 			zone: ".", query: exampleCom, want: true,
 		},
 		{
 			name: "com refers to example.com", resp: referralTo(exampleCom),
 			zone: "com.", query: wwwExampleCom, want: true,
 		},
 		{
 			name: "referral back to the zone", resp: referralTo(exampleCom),
 			zone: exampleCom, query: exampleCom, want: false,
 		},
 		{
 			name: "referral up to the root", resp: referralTo("."),
 			zone: exampleCom, query: exampleCom, want: false,
 		},
 		{
 			name: "referral sideways", resp: referralTo("net."),
 			zone: ".", query: exampleCom, want: false,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			assert.Equal(t, tt.want,
 				resolver.UsableReply(tt.resp, tt.zone, tt.query),
 			)
 		})
 	}
 }
 // TestNSSetFrom checks which NS set a reply gives for a domain; a set
 // that is not empty ends the walk. The referral to example.com that
 // com's servers all send alike gives its delegation, so the set is the
 // same whichever of them answered, and example.com's own servers, which
 // can disagree, are not asked.
 func TestNSSetFrom(t *testing.T) {
 	t.Parallel()
 	answer := new(dns.Msg)
 	answer.Authoritative = true
 	answer.Answer = []dns.RR{nsRecord(exampleCom)}
 	tests := []struct {
 		name   string
 		resp   *dns.Msg
 		domain string
 		want   []string
 	}{
 		{
 			name: "com refers to example.com", resp: referralTo(exampleCom),
 			domain: exampleCom, want: []string{exampleNS},
 		},
 		{
 			name: "com refers on, for www.example.com",
 			resp: referralTo(exampleCom), domain: wwwExampleCom,
 			want: nil,
 		},
 		{
 			name: "answer from a server that holds example.com",
 			resp: answer, domain: exampleCom,
 			want: []string{exampleNS},
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			assert.ElementsMatch(t, tt.want,
 				resolver.NSSetFrom(tt.resp, tt.domain),
 			)
 		})
 	}
 }
 func TestExtractRecordValue_LetterCase(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
 		name string
 		rr   dns.RR
 		want string
 	}{
 		{
 			name: "MX target lower-cased",
 			rr:   &dns.MX{Preference: 1, Mx: "ASPMX.L.GOOGLE.COM."},
 			want: "1 aspmx.l.google.com.",
 		},
 		{
 			name: "NS target lower-cased",
 			rr:   &dns.NS{Ns: "x.ns.joker.COM."},
 			want: "x.ns.joker.com.",
 		},
 		{
 			name: "CNAME target lower-cased",
 			rr:   &dns.CNAME{Target: "WWW.Example.Com."},
 			want: "www.example.com.",
 		},
 		{
 			name: "SRV target lower-cased",
 			rr: &dns.SRV{
 				Priority: 10, Weight: 5, Port: 443,
 				Target: "SIP.Example.Com.",
 			},
 			want: "10 5 443 sip.example.com.",
 		},
 		{
 			name: "TXT value keeps its case",
 			rr:   &dns.TXT{Txt: []string{"Verify=AbC123"}},
 			want: "Verify=AbC123",
 		},
 		{
 			name: "CAA value keeps its case",
 			rr:   &dns.CAA{Flag: 0, Tag: "issue", Value: "LetsEncrypt.org"},
 			want: `0 issue "LetsEncrypt.org"`,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			assert.Equal(t, tt.want, resolver.ExtractRecordValue(tt.rr))
 		})
 	}
 }
 // TestShuffled shuffles the root servers with many seeds. Every order
 // must hold each root server once, so each is tried before a
 // resolution fails; each root server must come first for some seed, so
 // no one root server gets every first query; and the list passed in
 // must be left as it was.
 func TestShuffled(t *testing.T) {
 	t.Parallel()
 	const seeds = 1000
 	roots := resolver.RootServerList()
 	before := slices.Clone(roots)
 	first := make(map[string]bool)
 	for seed := range uint64(seeds) {
 		rng := rand.New(rand.NewPCG(seed, 0)) //nolint:gosec // seeded on purpose
 		order := resolver.Shuffled(roots, rng.Shuffle)
 		assert.ElementsMatch(t, roots, order)
 		first[order[0]] = true
 	}
 	assert.Len(t, first, len(roots))
 	assert.Equal(t, before, roots)
 }
@@ -1,192 +0,0 @@
 package resolver_test
 import (
 	"testing"
 	"github.com/stretchr/testify/assert"
 	"sneak.berlin/go/dnswatcher/internal/resolver"
 )
 // Tests for the live-DNS harness in livedns_test.go itself. These
 // exercise pure logic; they perform no DNS resolution of any kind, so
 // they neither mock DNS nor depend on it.
 // Names for the synthetic status maps below. Nothing is ever queried
 // at them: they are map keys handed to the package's pure counting
 // helpers, not a stand-in for a nameserver.
 const (
 	nsExample1 = "ns1.example."
 	nsExample2 = "ns2.example."
 	nsExample3 = "ns3.example."
 	nsExample4 = "ns4.example."
 )
 func TestLiveQuorumIsStrictMajority(t *testing.T) {
 	t.Parallel()
 	cases := map[int]int{
 		0:  1,
 		1:  1,
 		2:  2,
 		3:  2,
 		4:  3,
 		5:  3,
 		13: 7,
 	}
 	for total, want := range cases {
 		assert.Equal(
 			t, want, liveQuorum(total),
 			"liveQuorum(%d)", total,
 		)
 	}
 }
 func TestStatusCountingIgnoresSilentNameservers(t *testing.T) {
 	t.Parallel()
 	results := map[string]*resolver.NameserverResponse{
 		nsExample1: {
 			Nameserver: nsExample1,
 			Status:     resolver.StatusOK,
 		},
 		nsExample2: {
 			Nameserver: nsExample2,
 			Status:     resolver.StatusOK,
 		},
 		nsExample3: {
 			Nameserver: nsExample3,
 			Status:     resolver.StatusTimeout,
 		},
 		nsExample4: {
 			Nameserver: nsExample4,
 			Status:     resolver.StatusError,
 		},
 	}
 	assert.Equal(
 		t, 2, countStatus(results, resolver.StatusOK),
 	)
 	assert.Equal(
 		t, 0, countStatus(results, resolver.StatusNXDomain),
 	)
 	// Two of four answered, which is short of the quorum of
 	// three: this is the state that triggers a retry rather
 	// than an assertion failure.
 	assert.Equal(t, 2, answeredCount(results))
 	assert.Less(t, answeredCount(results), liveQuorum(len(results)))
 	assert.Equal(
 		t,
 		"ns1.example.=ok ns2.example.=ok "+
 			"ns3.example.=timeout ns4.example.=error",
 		describeStatuses(results),
 	)
 }
 // TestUnsanctionedStatusesRejectsWrongAnswers is the regression test
 // for the defect this allowlist exists to prevent: a minority of
 // nameservers answering WRONGLY while quorum keeps the suite green.
 // nodata is the case that motivated it — it is a wrong answer, not
 // silence, and it was previously banned by neither test.
 func TestUnsanctionedStatusesRejectsWrongAnswers(t *testing.T) {
 	t.Parallel()
 	// Four nameservers, three OK and one answering nodata: a
 	// quorum of three is satisfied and no NXDOMAIN is present, so
 	// the old blocklist assertions both passed on this input.
 	results := map[string]*resolver.NameserverResponse{
 		nsExample1: {
 			Nameserver: nsExample1,
 			Status:     resolver.StatusOK,
 		},
 		nsExample2: {
 			Nameserver: nsExample2,
 			Status:     resolver.StatusOK,
 		},
 		nsExample3: {
 			Nameserver: nsExample3,
 			Status:     resolver.StatusOK,
 		},
 		nsExample4: {
 			Nameserver: nsExample4,
 			Status:     resolver.StatusNoData,
 		},
 	}
 	assert.GreaterOrEqual(
 		t,
 		countStatus(results, resolver.StatusOK),
 		liveQuorum(len(results)),
 	)
 	assert.Zero(t, countStatus(results, resolver.StatusNXDomain))
 	// nodata is an ANSWER, so it never triggers a retry: nothing
 	// but the allowlist stands between it and a false green.
 	assert.Equal(t, len(results), answeredCount(results))
 	assert.Equal(
 		t,
 		[]string{nsExample4 + "=nodata"},
 		unsanctionedStatuses(
 			results,
 			resolver.StatusOK,
 			resolver.StatusTimeout,
 			resolver.StatusError,
 		),
 		"nodata must be reported as an unsanctioned status",
 	)
 }
 func TestUnsanctionedStatusesToleratesSilenceOnly(t *testing.T) {
 	t.Parallel()
 	results := map[string]*resolver.NameserverResponse{
 		nsExample1: {
 			Nameserver: nsExample1,
 			Status:     resolver.StatusNXDomain,
 		},
 		nsExample2: {
 			Nameserver: nsExample2,
 			Status:     resolver.StatusTimeout,
 		},
 		nsExample3: {
 			Nameserver: nsExample3,
 			Status:     resolver.StatusError,
 		},
 	}
 	allowed := []string{
 		resolver.StatusNXDomain,
 		resolver.StatusTimeout,
 		resolver.StatusError,
 	}
 	assert.Empty(
 		t,
 		unsanctionedStatuses(results, allowed...),
 		"timeout and error are non-answers and are tolerated",
 	)
 	// The same silent nameservers do not count towards a quorum.
 	assert.Equal(t, 1, answeredCount(results))
 	// An unknown status is treated as silence by answeredCount —
 	// so it retries and fails loudly — and is unsanctioned by the
 	// allowlist rather than quietly permitted.
 	const laterStatus = "some-status-added-later"
 	results[nsExample4] = &resolver.NameserverResponse{
 		Nameserver: nsExample4,
 		Status:     laterStatus,
 	}
 	assert.Equal(t, 1, answeredCount(results))
 	assert.Equal(
 		t,
 		[]string{nsExample4 + "=" + laterStatus},
 		unsanctionedStatuses(results, allowed...),
 	)
 }
@@ -1,437 +0,0 @@
 package resolver_test
 import (
 	"context"
 	"errors"
 	"fmt"
 	"slices"
 	"sort"
 	"strings"
 	"testing"
 	"sneak.berlin/go/dnswatcher/internal/livednstest"
 	"sneak.berlin/go/dnswatcher/internal/resolver"
 )
 // ----------------------------------------------------------------
 // Live DNS test support
 // ----------------------------------------------------------------
 //
 // Tests that look something up in DNS query live DNS servers, never a
 // stand-in; logic that works on record data may be tested on that
 // data with no lookup (see TESTING.md). Each live operation below goes
 // through livednstest.Retry, which bounds how many resolutions are in
 // flight at once and retries an operation that got no answer (see
 // package livednstest).
 //
 // Where an assertion spans several independent nameservers, a quorum
 // is enough: a strict majority answering as expected. A server that
 // fails to answer is tolerated, while a server that answers *wrongly*
 // still fails the test.
 //
 // That tolerance is expressed as an ALLOWLIST of sanctioned statuses,
 // never as a blocklist of known-bad ones. A blocklist bans the one
 // wrong answer its author thought of and silently admits every other
 // status, including any added to the resolver later; an allowlist
 // fails on anything nobody explicitly sanctioned. Silence (timeout,
 // error) is the only thing quorum exists to tolerate. A *wrong
 // answer* — nxdomain for a name that exists, ok for one that does
 // not, nodata for either — is never tolerated at any count.
 // minNameservers is the smallest nameserver count a well-run zone is
 // expected to publish.
 const minNameservers = 2
 // errLiveNoQuorum reports that too few of a domain's nameservers
 // answered for a quorum assertion to be made.
 var errLiveNoQuorum = errors.New("no nameserver quorum")
 // liveQuorum is how many of total nameservers must agree for a
 // multi-nameserver assertion to hold: a strict majority.
 func liveQuorum(total int) int {
 	if total < 1 {
 		return 1
 	}
 	return total/2 + 1
 }
 // countStatus counts the responses carrying the given status.
 func countStatus(
 	results map[string]*resolver.NameserverResponse,
 	status string,
 ) int {
 	n := 0
 	for _, resp := range results {
 		if resp.Status == status {
 			n++
 		}
 	}
 	return n
 }
 // liveAnswerStatuses is the closed set of statuses that count as a
 // nameserver having ANSWERED at all, whether or not the test agrees
 // with the answer. It is deliberately an allowlist: a status added
 // to the resolver later is treated as silence, so it can only ever
 // cause a retry and then a loud failure, never a quiet pass.
 func liveAnswerStatuses() []string {
 	return []string{
 		resolver.StatusOK,
 		resolver.StatusNXDomain,
 		resolver.StatusNoData,
 	}
 }
 // answeredCount counts the nameservers that produced an answer of
 // any kind, as opposed to failing or timing out.
 func answeredCount(
 	results map[string]*resolver.NameserverResponse,
 ) int {
 	answers := liveAnswerStatuses()
 	n := 0
 	for _, resp := range results {
 		if slices.Contains(answers, resp.Status) {
 			n++
 		}
 	}
 	return n
 }
 // unsanctionedStatuses returns "nameserver=status" for every result
 // whose status the caller did not explicitly sanction, sorted for a
 // stable failure message. Callers pass the full closed set they will
 // accept — the expected answer plus whichever non-answers (timeout,
 // error) quorum is allowed to tolerate — so that any status outside
 // it fails the test by name.
 func unsanctionedStatuses(
 	results map[string]*resolver.NameserverResponse,
 	allowed ...string,
 ) []string {
 	offenders := make([]string, 0, len(results))
 	for ns, resp := range results {
 		if slices.Contains(allowed, resp.Status) {
 			continue
 		}
 		offenders = append(
 			offenders, fmt.Sprintf("%s=%s", ns, resp.Status),
 		)
 	}
 	sort.Strings(offenders)
 	return offenders
 }
 // describeStatuses renders per-nameserver statuses for use in
 // assertion failure messages.
 func describeStatuses(
 	results map[string]*resolver.NameserverResponse,
 ) string {
 	parts := make([]string, 0, len(results))
 	for ns, resp := range results {
 		parts = append(
 			parts, fmt.Sprintf("%s=%s", ns, resp.Status),
 		)
 	}
 	sort.Strings(parts)
 	return strings.Join(parts, " ")
 }
 // ----------------------------------------------------------------
 // Live operation wrappers
 // ----------------------------------------------------------------
 // liveFindAuthoritative resolves a domain's authoritative
 // nameservers, retrying until the delegation chain can be walked.
 func liveFindAuthoritative(
 	t *testing.T,
 	r *resolver.Resolver,
 	domain string,
 ) []string {
 	t.Helper()
 	var out []string
 	livednstest.Retry(
 		t,
 		"FindAuthoritativeNameservers("+domain+")",
 		func(ctx context.Context) error {
 			ns, err := r.FindAuthoritativeNameservers(ctx, domain)
 			if err != nil {
 				return err
 			}
 			if len(ns) == 0 {
 				return fmt.Errorf(
 					"%w: %s has no nameservers",
 					livednstest.ErrNoAnswer, domain,
 				)
 			}
 			out = ns
 			return nil
 		},
 	)
 	return out
 }
 // liveLookupNS is liveFindAuthoritative through the LookupNS entry
 // point, so that both entry points stay independently exercised.
 func liveLookupNS(
 	t *testing.T,
 	r *resolver.Resolver,
 	domain string,
 ) []string {
 	t.Helper()
 	var out []string
 	livednstest.Retry(
 		t,
 		"LookupNS("+domain+")",
 		func(ctx context.Context) error {
 			ns, err := r.LookupNS(ctx, domain)
 			if err != nil {
 				return err
 			}
 			if len(ns) == 0 {
 				return fmt.Errorf(
 					"%w: %s has no nameservers",
 					livednstest.ErrNoAnswer, domain,
 				)
 			}
 			out = ns
 			return nil
 		},
 	)
 	return out
 }
 // liveQueryNameserver queries one nameserver, retrying while that
 // nameserver fails to answer. NXDOMAIN and NODATA are answers and
 // are returned to the caller to assert on.
 //
 // QueryNameserver sends one query per record type, so one lost query
 // leaves its type out of an answer that is otherwise fine. A test names
 // in types the record types it reads; an answer holding records of none
 // of them is retried too.
 func liveQueryNameserver(
 	t *testing.T,
 	r *resolver.Resolver,
 	nameserver string,
 	hostname string,
 	types ...string,
 ) *resolver.NameserverResponse {
 	t.Helper()
 	what := fmt.Sprintf(
 		"QueryNameserver(%s, %s)", nameserver, hostname,
 	)
 	var out *resolver.NameserverResponse
 	livednstest.Retry(
 		t,
 		what,
 		func(ctx context.Context) error {
 			resp, err := r.QueryNameserver(
 				ctx, nameserver, hostname,
 			)
 			if err != nil {
 				return err
 			}
 			if resp.Status == resolver.StatusTimeout ||
 				resp.Status == resolver.StatusError {
 				return fmt.Errorf(
 					"%w: %s returned %s: %s",
 					livednstest.ErrNoAnswer, nameserver,
 					resp.Status, resp.Error,
 				)
 			}
 			hasRecords := func(recordType string) bool {
 				return len(resp.Records[recordType]) > 0
 			}
 			if len(types) > 0 && !slices.ContainsFunc(types, hasRecords) {
 				return fmt.Errorf(
 					"%w: %s returned no %s records",
 					livednstest.ErrNoAnswer, nameserver,
 					strings.Join(types, " or "),
 				)
 			}
 			out = resp
 			return nil
 		},
 	)
 	return out
 }
 // liveQueryAllNameservers queries every authoritative nameserver
 // for a hostname, retrying until a quorum of them has answered.
 // Individual nameservers that stay silent are left in the result
 // for the caller to account for.
 func liveQueryAllNameservers(
 	t *testing.T,
 	r *resolver.Resolver,
 	hostname string,
 ) map[string]*resolver.NameserverResponse {
 	t.Helper()
 	var out map[string]*resolver.NameserverResponse
 	livednstest.Retry(
 		t,
 		"QueryAllNameservers("+hostname+")",
 		func(ctx context.Context) error {
 			results, err := r.QueryAllNameservers(ctx, hostname)
 			if err != nil {
 				return err
 			}
 			if len(results) == 0 {
 				return fmt.Errorf(
 					"%w: no nameservers queried for %s",
 					livednstest.ErrNoAnswer, hostname,
 				)
 			}
 			answered := answeredCount(results)
 			if answered < liveQuorum(len(results)) {
 				return fmt.Errorf(
 					"%w: %d of %d answered: %s",
 					errLiveNoQuorum, answered,
 					len(results), describeStatuses(results),
 				)
 			}
 			out = results
 			return nil
 		},
 	)
 	return out
 }
 // liveResolveIPs resolves a hostname that is expected to have
 // addresses, retrying until at least one is returned.
 func liveResolveIPs(
 	t *testing.T,
 	r *resolver.Resolver,
 	hostname string,
 ) []string {
 	t.Helper()
 	var out []string
 	livednstest.Retry(
 		t,
 		"ResolveIPAddresses("+hostname+")",
 		func(ctx context.Context) error {
 			ips, err := r.ResolveIPAddresses(ctx, hostname)
 			if err != nil {
 				return err
 			}
 			if len(ips) == 0 {
 				return fmt.Errorf(
 					"%w: no addresses for %s",
 					livednstest.ErrNoAnswer, hostname,
 				)
 			}
 			out = ips
 			return nil
 		},
 	)
 	return out
 }
 // liveResolveIPsAllowingEmpty resolves a hostname that may legitimately
 // have no addresses, so the empty result is returned rather than
 // retried. Used for names that must not exist; the corresponding
 // QueryAllNameservers test is what proves the nameservers actively
 // said NXDOMAIN rather than merely staying silent.
 func liveResolveIPsAllowingEmpty(
 	t *testing.T,
 	r *resolver.Resolver,
 	hostname string,
 ) []string {
 	t.Helper()
 	var out []string
 	livednstest.Retry(
 		t,
 		"ResolveIPAddresses("+hostname+")",
 		func(ctx context.Context) error {
 			ips, err := r.ResolveIPAddresses(ctx, hostname)
 			if err != nil {
 				return err
 			}
 			out = ips
 			return nil
 		},
 	)
 	return out
 }
 // liveResolveNSIPs looks up the addresses of the nameservers named
 // names, retrying until there are at least atLeast of them: a name
 // whose lookup got no reply is left out of the result, not an error.
 func liveResolveNSIPs(
 	t *testing.T,
 	r *resolver.Resolver,
 	names []string,
 	atLeast int,
 ) []string {
 	t.Helper()
 	var out []string
 	livednstest.Retry(
 		t,
 		"ResolveNSIPs("+strings.Join(names, ", ")+")",
 		func(ctx context.Context) error {
 			ips := r.ResolveNSIPs(ctx, names)
 			if len(ips) < atLeast {
 				return fmt.Errorf(
 					"%w: %d addresses, expected at least %d",
 					livednstest.ErrNoAnswer, len(ips), atLeast,
 				)
 			}
 			out = ips
 			return nil
 		},
 	)
 	return out
 }
@@ -31,15 +31,11 @@ type Params struct {
 }
 // NameserverResponse holds one nameserver's response for a query.
 // FailedTypes lists the record types whose query got no usable reply,
 // and Records holds nothing for them: their records are not known. When
 // no record type got one, Status and Error say the nameserver failed.
 type NameserverResponse struct {
-	Nameserver  string
+	Nameserver string
-	Records     map[string][]string
+	Records    map[string][]string
-	FailedTypes []string
+	Status     string
-	Status      string
+	Error      string
 	Error       string
 }
 // Resolver performs iterative DNS resolution from root servers.
@@ -71,4 +67,17 @@ func NewFromLogger(log *slog.Logger) *Resolver {
 	}
 }
 // NewFromLoggerWithClient creates a Resolver with a custom DNS
 // client, useful for testing with mock DNS responses.
 func NewFromLoggerWithClient(
 	log *slog.Logger,
 	client DNSClient,
 ) *Resolver {
 	return &Resolver{
 		log:    log,
 		client: client,
 		tcp:    client,
 	}
 }
 // Method implementations are in iterative.go.
@@ -1,9 +1,7 @@
 package resolver_test
 import (
 	"bytes"
 	"context"
 	"fmt"
 	"log/slog"
 	"net"
 	"os"
@@ -16,7 +14,6 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"sneak.berlin/go/dnswatcher/internal/livednstest"
 	"sneak.berlin/go/dnswatcher/internal/resolver"
 )
@@ -35,17 +32,32 @@ func newTestResolver(t *testing.T) *resolver.Resolver {
 	return resolver.NewFromLogger(log)
 }
-// findOneNSForDomain picks one authoritative nameserver to aim a
+func testContext(t *testing.T) context.Context {
-// test at. Quorum handling lives in livedns_test.go, and the live-DNS
+	t.Helper()
-// retry and concurrency limit in package livednstest.
+
 	ctx, cancel := context.WithTimeout(
 		context.Background(), 60*time.Second,
 	)
 	t.Cleanup(cancel)
 	return ctx
 }
 func findOneNSForDomain(
 	t *testing.T,
 	r *resolver.Resolver,
 	ctx context.Context, //nolint:revive // test helper
 	domain string,
 ) string {
 	t.Helper()
-	return liveFindAuthoritative(t, r, domain)[0]
+	nameservers, err := r.FindAuthoritativeNameservers(
 		ctx, domain,
 	)
 	require.NoError(t, err)
 	require.NotEmpty(t, nameservers)
 	return nameservers[0]
 }
 // ----------------------------------------------------------------
@@ -58,7 +70,13 @@ func TestFindAuthoritativeNameservers_ValidDomain(
 	t.Parallel()
 	r := newTestResolver(t)
-	nameservers := liveFindAuthoritative(t, r, "google.com")
+	ctx := testContext(t)
 	nameservers, err := r.FindAuthoritativeNameservers(
 		ctx, "google.com",
 	)
 	require.NoError(t, err)
 	require.NotEmpty(t, nameservers)
 	hasGoogleNS := false
@@ -81,10 +99,13 @@ func TestFindAuthoritativeNameservers_Subdomain(
 	t.Parallel()
 	r := newTestResolver(t)
-	fromHost := liveFindAuthoritative(t, r, "www.google.com")
+	ctx := testContext(t)
 	fromZone := liveFindAuthoritative(t, r, "google.com")
-	assert.Equal(t, fromZone, fromHost)
+	nameservers, err := r.FindAuthoritativeNameservers(
 		ctx, "www.google.com",
 	)
 	require.NoError(t, err)
 	require.NotEmpty(t, nameservers)
 }
 func TestFindAuthoritativeNameservers_ReturnsSorted(
@@ -93,7 +114,12 @@ func TestFindAuthoritativeNameservers_ReturnsSorted(
 	t.Parallel()
 	r := newTestResolver(t)
-	nameservers := liveFindAuthoritative(t, r, "google.com")
+	ctx := testContext(t)
 	nameservers, err := r.FindAuthoritativeNameservers(
 		ctx, "google.com",
 	)
 	require.NoError(t, err)
 	assert.True(
 		t,
@@ -108,8 +134,17 @@ func TestFindAuthoritativeNameservers_Deterministic(
 	t.Parallel()
 	r := newTestResolver(t)
-	first := liveFindAuthoritative(t, r, "google.com")
+	ctx := testContext(t)
-	second := liveFindAuthoritative(t, r, "google.com")
+
 	first, err := r.FindAuthoritativeNameservers(
 		ctx, "google.com",
 	)
 	require.NoError(t, err)
 	second, err := r.FindAuthoritativeNameservers(
 		ctx, "google.com",
 	)
 	require.NoError(t, err)
 	assert.Equal(t, first, second)
 }
@@ -120,8 +155,17 @@ func TestFindAuthoritativeNameservers_TrailingDot(
 	t.Parallel()
 	r := newTestResolver(t)
-	ns1 := liveFindAuthoritative(t, r, "google.com")
+	ctx := testContext(t)
-	ns2 := liveFindAuthoritative(t, r, "google.com.")
+
 	ns1, err := r.FindAuthoritativeNameservers(
 		ctx, "google.com",
 	)
 	require.NoError(t, err)
 	ns2, err := r.FindAuthoritativeNameservers(
 		ctx, "google.com.",
 	)
 	require.NoError(t, err)
 	assert.Equal(t, ns1, ns2)
 }
@@ -132,7 +176,13 @@ func TestFindAuthoritativeNameservers_CloudflareDomain(
 	t.Parallel()
 	r := newTestResolver(t)
-	nameservers := liveFindAuthoritative(t, r, "cloudflare.com")
+	ctx := testContext(t)
 	nameservers, err := r.FindAuthoritativeNameservers(
 		ctx, "cloudflare.com",
 	)
 	require.NoError(t, err)
 	require.NotEmpty(t, nameservers)
 	for _, ns := range nameservers {
 		assert.True(t, strings.HasSuffix(ns, "."),
@@ -141,28 +191,6 @@ func TestFindAuthoritativeNameservers_CloudflareDomain(
 	}
 }
 // TestResolveNSIPs_EveryNameserver looks up the addresses of two of
 // google.com's nameservers together, as the walk does when a referral
 // names a zone's nameservers without their addresses, and compares them
 // with each looked up alone. Together they must give the addresses of
 // both, not only of the first that resolves, so that when one gives no
 // usable reply the walk goes on to the other.
 func TestResolveNSIPs_EveryNameserver(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
 	names := []string{"ns3.google.com.", "ns4.google.com."}
 	want := make([]string, 0, len(names))
 	for _, name := range names {
 		want = append(want, liveResolveNSIPs(t, r, []string{name}, 1)...)
 	}
 	got := liveResolveNSIPs(t, r, names, len(want))
 	assert.ElementsMatch(t, want, got)
 }
 // ----------------------------------------------------------------
 // QueryNameserver tests
 // ----------------------------------------------------------------
@@ -171,9 +199,13 @@ func TestQueryNameserver_BasicA(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	ns := findOneNSForDomain(t, r, "google.com")
+	ctx := testContext(t)
-	resp := liveQueryNameserver(t, r, ns, "www.google.com", "A", "CNAME")
+	ns := findOneNSForDomain(t, r, ctx, "google.com")
 	resp, err := r.QueryNameserver(
 		ctx, ns, "www.google.com",
 	)
 	require.NoError(t, err)
 	require.NotNil(t, resp)
 	assert.Equal(t, resolver.StatusOK, resp.Status)
@@ -190,8 +222,13 @@ func TestQueryNameserver_AAAA(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	ns := findOneNSForDomain(t, r, "cloudflare.com")
+	ctx := testContext(t)
-	resp := liveQueryNameserver(t, r, ns, "cloudflare.com", "AAAA")
+	ns := findOneNSForDomain(t, r, ctx, "cloudflare.com")
 	resp, err := r.QueryNameserver(
 		ctx, ns, "cloudflare.com",
 	)
 	require.NoError(t, err)
 	aaaaRecords := resp.Records["AAAA"]
 	require.NotEmpty(t, aaaaRecords,
@@ -210,8 +247,13 @@ func TestQueryNameserver_MX(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	ns := findOneNSForDomain(t, r, "google.com")
+	ctx := testContext(t)
-	resp := liveQueryNameserver(t, r, ns, "google.com", "MX")
+	ns := findOneNSForDomain(t, r, ctx, "google.com")
 	resp, err := r.QueryNameserver(
 		ctx, ns, "google.com",
 	)
 	require.NoError(t, err)
 	mxRecords := resp.Records["MX"]
 	require.NotEmpty(t, mxRecords,
@@ -223,8 +265,13 @@ func TestQueryNameserver_TXT(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	ns := findOneNSForDomain(t, r, "google.com")
+	ctx := testContext(t)
-	resp := liveQueryNameserver(t, r, ns, "google.com", "TXT")
+	ns := findOneNSForDomain(t, r, ctx, "google.com")
 	resp, err := r.QueryNameserver(
 		ctx, ns, "google.com",
 	)
 	require.NoError(t, err)
 	txtRecords := resp.Records["TXT"]
 	require.NotEmpty(t, txtRecords,
@@ -246,268 +293,33 @@ func TestQueryNameserver_TXT(t *testing.T) {
 	)
 }
 // TestQueryNameserver_TruncatedReplyWhoseTCPRetryFails asks a google.com
 // nameserver about google.com with a resolver whose retries over TCP
 // fail. google.com's TXT records do not fit in a reply over UDP, so TXT
 // is reported as failed, holding none of the records that fit, and
 // logged with the reason, while the nameserver, which answered the other
 // types, is ok.
 func TestQueryNameserver_TruncatedReplyWhoseTCPRetryFails(t *testing.T) {
 	t.Parallel()
 	ns := findOneNSForDomain(t, newTestResolver(t), "google.com")
 	var logs bytes.Buffer
 	r := resolver.NewWithFailingTCP(slog.New(slog.NewTextHandler(&logs, nil)))
 	resp := liveQueryNameserver(t, r, ns, "google.com")
 	assert.Equal(t, resolver.StatusOK, resp.Status)
 	assert.Contains(t, resp.FailedTypes, "TXT")
 	assert.NotContains(t, resp.Records, "TXT")
 	assert.Contains(t, logs.String(),
 		"hostname=google.com. nameserver="+ns+" type=TXT error=",
 	)
 }
 func TestQueryNameserver_NXDomain(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	ns := findOneNSForDomain(t, r, "google.com")
+	ctx := testContext(t)
-	resp := liveQueryNameserver(
+	ns := findOneNSForDomain(t, r, ctx, "google.com")
-		t, r, ns, "this-surely-does-not-exist-xyz.google.com",
+
 	resp, err := r.QueryNameserver(
 		ctx, ns,
 		"this-surely-does-not-exist-xyz.google.com",
 	)
 	require.NoError(t, err)
 	assert.Equal(t, resolver.StatusNXDomain, resp.Status)
 }
 // TestQueryNameserver_Refused asks a google.com nameserver about
 // cloudflare.com, a zone it does not serve, which it refuses. Refusing
 // is a failure to answer, not an answer with no records.
 func TestQueryNameserver_Refused(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
 	ns := findOneNSForDomain(t, r, "google.com")
 	var resp *resolver.NameserverResponse
 	livednstest.Retry(
 		t,
 		"QueryNameserver("+ns+", cloudflare.com)",
 		func(ctx context.Context) error {
 			var err error
 			resp, err = r.QueryNameserver(ctx, ns, "cloudflare.com")
 			if err != nil {
 				return err
 			}
 			// A timeout or a network error is no reply at all.
 			if resp.Status == resolver.StatusTimeout ||
 				strings.HasPrefix(resp.Error, "network error") {
 				return fmt.Errorf(
 					"%w: %s: %s",
 					livednstest.ErrNoAnswer, ns, resp.Error,
 				)
 			}
 			return nil
 		},
 	)
 	assert.Equal(t, resolver.StatusError, resp.Status)
 	assert.Equal(t, "server returned REFUSED", resp.Error)
 }
 // TestQueryNameserverIP_RecursiveResolverRefused asks Quad9, a public
 // recursive resolver, about google.com at both of its addresses. Quad9
 // refuses a query that does not ask for recursion and answers one that
 // does. The resolver never asks for recursion, so it must be reported
 // as refusing, never as answering.
 func TestQueryNameserverIP_RecursiveResolverRefused(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
 	for _, ip := range []string{"9.9.9.9", "149.112.112.112"} {
 		var resp *resolver.NameserverResponse
 		livednstest.Retry(
 			t,
 			"QueryNameserverIP("+ip+", google.com)",
 			func(ctx context.Context) error {
 				var err error
 				resp, err = r.QueryNameserverIP(
 					ctx, ip, ip, "google.com",
 				)
 				if err != nil {
 					return err
 				}
 				// A timeout or a network error is no reply at all.
 				if resp.Status == resolver.StatusTimeout ||
 					strings.HasPrefix(resp.Error, "network error") {
 					return fmt.Errorf(
 						"%w: %s: %s",
 						livednstest.ErrNoAnswer, ip, resp.Error,
 					)
 				}
 				return nil
 			},
 		)
 		assert.Equal(t, resolver.StatusError, resp.Status, ip)
 		assert.Equal(t, "server returned REFUSED", resp.Error, ip)
 	}
 }
 // googleNameserverIPv4s returns the IPv4 addresses of google.com's
 // nameservers, the only addresses the resolver asks servers at.
 func googleNameserverIPv4s(t *testing.T, r *resolver.Resolver) []string {
 	t.Helper()
 	names := liveFindAuthoritative(t, r, "google.com")
 	return liveResolveNSIPs(t, r, names, len(names))
 }
 // TestQueryServers_EveryServerRefused asks all of google.com's
 // nameservers about cloudflare.com, a zone they do not serve, which
 // they all refuse. The error says every server refused; it is not
 // ErrIntercepted, which only the root servers refusing shows.
 func TestQueryServers_EveryServerRefused(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
 	servers := googleNameserverIPv4s(t, r)
 	var err error
 	livednstest.Retry(
 		t,
 		"QueryServers(google.com servers, cloudflare.com)",
 		func(ctx context.Context) error {
 			_, err = r.QueryServers(
 				ctx, servers, "google.com.", "cloudflare.com.",
 				dns.TypeNS,
 			)
 			// When not every server refused, one may have given no
 			// reply at all, so the attempt is tried again.
 			if err != nil &&
 				!strings.HasPrefix(err.Error(), "every server of") {
 				return fmt.Errorf(
 					"%w: %w", livednstest.ErrNoAnswer, err,
 				)
 			}
 			return nil
 		},
 	)
 	require.ErrorIs(t, err, resolver.ErrRefused)
 	require.NotErrorIs(t, err, resolver.ErrIntercepted)
 	require.EqualError(
 		t, err,
 		"every server of google.com. refused a query for "+
 			"cloudflare.com.: dns query refused",
 	)
 }
 // TestQueryServers_EveryRootServerRefused passes google.com's
 // nameservers to QueryServers as the servers of the root zone. They
 // refuse a query about cloudflare.com, as root servers would if
 // something on the network answered in their place, so the error is
 // ErrIntercepted.
 func TestQueryServers_EveryRootServerRefused(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
 	servers := googleNameserverIPv4s(t, r)
 	var err error
 	livednstest.Retry(
 		t,
 		"QueryServers(google.com servers as root servers, cloudflare.com)",
 		func(ctx context.Context) error {
 			_, err = r.QueryServers(
 				ctx, servers, ".", "cloudflare.com.", dns.TypeNS,
 			)
 			// When not every server refused, one may have given no
 			// reply at all, so the attempt is tried again. Both errors
 			// for every server refusing say "refused a query for".
 			if err != nil &&
 				!strings.Contains(err.Error(), "refused a query for") {
 				return fmt.Errorf(
 					"%w: %w", livednstest.ErrNoAnswer, err,
 				)
 			}
 			return nil
 		},
 	)
 	require.ErrorIs(t, err, resolver.ErrIntercepted)
 	require.EqualError(
 		t, err,
 		"every root server refused a query for cloudflare.com.: "+
 			"this network intercepts DNS queries",
 	)
 }
 // TestQueryServers_NotEveryRootServerRefused passes google.com's
 // nameservers and 192.0.2.1 to QueryServers as the servers of the root
 // zone. The google.com nameservers refuse a query about cloudflare.com,
 // but nothing answers at 192.0.2.1, a documentation address, so not
 // every server refused, wherever 192.0.2.1 falls in the random order:
 // the error is not ErrIntercepted and does not say every server refused.
 func TestQueryServers_NotEveryRootServerRefused(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
 	servers := googleNameserverIPv4s(t, r)
 	servers = append(servers, "192.0.2.1")
 	var err error
 	livednstest.Retry(
 		t,
 		"QueryServers(google.com servers and 192.0.2.1, cloudflare.com)",
 		func(ctx context.Context) error {
 			_, err = r.QueryServers(
 				ctx, servers, ".", "cloudflare.com.", dns.TypeNS,
 			)
 			// An attempt that ran out of time may not have asked every
 			// server, so it is tried again.
 			if ctx.Err() != nil {
 				return fmt.Errorf(
 					"%w: %w", livednstest.ErrNoAnswer, err,
 				)
 			}
 			return nil
 		},
 	)
 	require.Error(t, err)
 	require.NotErrorIs(t, err, resolver.ErrIntercepted)
 	// Both errors for every server refusing say "refused a query for".
 	require.NotContains(t, err.Error(), "refused a query for")
 }
 func TestQueryNameserver_RecordsSorted(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	ns := findOneNSForDomain(t, r, "google.com")
+	ctx := testContext(t)
-	resp := liveQueryNameserver(t, r, ns, "google.com")
+	ns := findOneNSForDomain(t, r, ctx, "google.com")
 	resp, err := r.QueryNameserver(
 		ctx, ns, "google.com",
 	)
 	require.NoError(t, err)
 	for recordType, values := range resp.Records {
 		assert.True(
@@ -524,8 +336,13 @@ func TestQueryNameserver_ResponseIncludesNameserver(
 	t.Parallel()
 	r := newTestResolver(t)
-	ns := findOneNSForDomain(t, r, "cloudflare.com")
+	ctx := testContext(t)
-	resp := liveQueryNameserver(t, r, ns, "cloudflare.com")
+	ns := findOneNSForDomain(t, r, ctx, "cloudflare.com")
 	resp, err := r.QueryNameserver(
 		ctx, ns, "cloudflare.com",
 	)
 	require.NoError(t, err)
 	assert.Equal(t, ns, resp.Nameserver)
 }
@@ -536,10 +353,14 @@ func TestQueryNameserver_EmptyRecordsOnNXDomain(
 	t.Parallel()
 	r := newTestResolver(t)
-	ns := findOneNSForDomain(t, r, "google.com")
+	ctx := testContext(t)
-	resp := liveQueryNameserver(
+	ns := findOneNSForDomain(t, r, ctx, "google.com")
-		t, r, ns, "this-surely-does-not-exist-xyz.google.com",
+
 	resp, err := r.QueryNameserver(
 		ctx, ns,
 		"this-surely-does-not-exist-xyz.google.com",
 	)
 	require.NoError(t, err)
 	totalRecords := 0
 	for _, values := range resp.Records {
@@ -553,9 +374,18 @@ func TestQueryNameserver_TrailingDotHandling(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	ns := findOneNSForDomain(t, r, "google.com")
+	ctx := testContext(t)
-	resp1 := liveQueryNameserver(t, r, ns, "google.com")
+	ns := findOneNSForDomain(t, r, ctx, "google.com")
-	resp2 := liveQueryNameserver(t, r, ns, "google.com.")
+
 	resp1, err := r.QueryNameserver(
 		ctx, ns, "google.com",
 	)
 	require.NoError(t, err)
 	resp2, err := r.QueryNameserver(
 		ctx, ns, "google.com.",
 	)
 	require.NoError(t, err)
 	assert.Equal(t, resp1.Status, resp2.Status)
 }
@@ -568,9 +398,15 @@ func TestQueryAllNameservers_ReturnsAllNS(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	results := liveQueryAllNameservers(t, r, "google.com")
+	ctx := testContext(t)
-	assert.GreaterOrEqual(t, len(results), minNameservers)
+	results, err := r.QueryAllNameservers(
 		ctx, "google.com",
 	)
 	require.NoError(t, err)
 	require.NotEmpty(t, results)
 	assert.GreaterOrEqual(t, len(results), 2)
 	for ns, resp := range results {
 		assert.Equal(t, ns, resp.Nameserver)
@@ -580,57 +416,19 @@ func TestQueryAllNameservers_ReturnsAllNS(t *testing.T) {
 func TestQueryAllNameservers_AllReturnOK(t *testing.T) {
 	t.Parallel()
-	// The last two names are in zones other than their last two
+	r := newTestResolver(t)
-	// labels: google.co.uk, under the two-label suffix co.uk, and
+	ctx := testContext(t)
 	// compute-1.amazonaws.com, which amazonaws.com delegates to other
 	// servers and which has a host name for each of its addresses.
 	// Servers above a name's zone only refer onward, which gives
 	// nodata, so ok shows the name was asked at its own zone's
 	// servers.
 	hostnames := []string{
 		"google.com",
 		"www.google.co.uk",
 		"ec2-3-80-0-1.compute-1.amazonaws.com",
 	}
-	for _, hostname := range hostnames {
+	results, err := r.QueryAllNameservers(
-		t.Run(hostname, func(t *testing.T) {
+		ctx, "google.com",
-			t.Parallel()
+	)
 	require.NoError(t, err)
-			r := newTestResolver(t)
+	for ns, resp := range results {
-			results := liveQueryAllNameservers(t, r, hostname)
+		assert.Equal(
-
+			t, resolver.StatusOK, resp.Status,
-			// A quorum, not unanimity: one authoritative server
+			"NS %s should return OK", ns,
-			// being slow or rate-limiting us is a property of the
+		)
 			// live internet, not a resolver defect.
 			assert.GreaterOrEqual(
 				t,
 				countStatus(results, resolver.StatusOK),
 				liveQuorum(len(results)),
 				"a quorum of nameservers should answer OK: %s",
 				describeStatuses(results),
 			)
 			// Quorum tolerates SILENCE only. Every individual
 			// result must be either the expected answer or a
 			// non-answer: ok, timeout or error, and nothing else.
 			// Stated as a closed allowlist so that a wrong answer
 			// no one thought to ban — nxdomain and nodata today,
 			// any status added later — fails here rather than
 			// sliding through under the quorum.
 			assert.Empty(
 				t,
 				unsanctionedStatuses(
 					results,
 					resolver.StatusOK,
 					resolver.StatusTimeout,
 					resolver.StatusError,
 				),
 				"every nameserver must answer OK or not answer "+
 					"at all: %s",
 				describeStatuses(results),
 			)
 		})
 	}
 }
@@ -640,34 +438,20 @@ func TestQueryAllNameservers_NXDomainFromAllNS(
 	t.Parallel()
 	r := newTestResolver(t)
-	results := liveQueryAllNameservers(
+	ctx := testContext(t)
 		t, r, "this-surely-does-not-exist-xyz.google.com",
 	)
-	assert.GreaterOrEqual(
+	results, err := r.QueryAllNameservers(
-		t,
+		ctx,
-		countStatus(results, resolver.StatusNXDomain),
+		"this-surely-does-not-exist-xyz.google.com",
 		liveQuorum(len(results)),
 		"a quorum of nameservers should report NXDOMAIN: %s",
 		describeStatuses(results),
 	)
 	require.NoError(t, err)
-	// Silence is tolerated; any actual answer other than NXDOMAIN
+	for ns, resp := range results {
-	// is not. Closed allowlist for the same reason as above: a
+		assert.Equal(
-	// server answering `ok` or `nodata` for a name that must not
+			t, resolver.StatusNXDomain, resp.Status,
-	// exist is a wrong answer, not a slow one.
+			"NS %s should return nxdomain", ns,
-	assert.Empty(
+		)
-		t,
+	}
 		unsanctionedStatuses(
 			results,
 			resolver.StatusNXDomain,
 			resolver.StatusTimeout,
 			resolver.StatusError,
 		),
 		"every nameserver must report NXDOMAIN or not answer "+
 			"at all: %s",
 		describeStatuses(results),
 	)
 }
 // ----------------------------------------------------------------
@@ -678,7 +462,11 @@ func TestLookupNS_ValidDomain(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	nameservers := liveLookupNS(t, r, "google.com")
+	ctx := testContext(t)
 	nameservers, err := r.LookupNS(ctx, "google.com")
 	require.NoError(t, err)
 	require.NotEmpty(t, nameservers)
 	for _, ns := range nameservers {
 		assert.True(t, strings.HasSuffix(ns, "."),
@@ -691,7 +479,10 @@ func TestLookupNS_Sorted(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	nameservers := liveLookupNS(t, r, "google.com")
+	ctx := testContext(t)
 	nameservers, err := r.LookupNS(ctx, "google.com")
 	require.NoError(t, err)
 	assert.True(t, sort.StringsAreSorted(nameservers))
 }
@@ -700,8 +491,15 @@ func TestLookupNS_MatchesFindAuthoritative(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	fromLookup := liveLookupNS(t, r, "google.com")
+	ctx := testContext(t)
-	fromFind := liveFindAuthoritative(t, r, "google.com")
+
 	fromLookup, err := r.LookupNS(ctx, "google.com")
 	require.NoError(t, err)
 	fromFind, err := r.FindAuthoritativeNameservers(
 		ctx, "google.com",
 	)
 	require.NoError(t, err)
 	assert.Equal(t, fromFind, fromLookup)
 }
@@ -714,7 +512,11 @@ func TestResolveIPAddresses_ReturnsIPs(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	ips := liveResolveIPs(t, r, "google.com")
+	ctx := testContext(t)
 	ips, err := r.ResolveIPAddresses(ctx, "google.com")
 	require.NoError(t, err)
 	require.NotEmpty(t, ips)
 	for _, ip := range ips {
 		parsed := net.ParseIP(ip)
@@ -728,7 +530,10 @@ func TestResolveIPAddresses_Deduplicated(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	ips := liveResolveIPs(t, r, "google.com")
+	ctx := testContext(t)
 	ips, err := r.ResolveIPAddresses(ctx, "google.com")
 	require.NoError(t, err)
 	seen := make(map[string]bool)
@@ -742,7 +547,10 @@ func TestResolveIPAddresses_Sorted(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	ips := liveResolveIPs(t, r, "google.com")
+	ctx := testContext(t)
 	ips, err := r.ResolveIPAddresses(ctx, "google.com")
 	require.NoError(t, err)
 	assert.True(t, sort.StringsAreSorted(ips))
 }
@@ -753,10 +561,13 @@ func TestResolveIPAddresses_NXDomainReturnsEmpty(
 	t.Parallel()
 	r := newTestResolver(t)
-	ips := liveResolveIPsAllowingEmpty(
+	ctx := testContext(t)
 		t, r, "this-surely-does-not-exist-xyz.google.com",
 	)
 	ips, err := r.ResolveIPAddresses(
 		ctx,
 		"this-surely-does-not-exist-xyz.google.com",
 	)
 	require.NoError(t, err)
 	assert.Empty(t, ips)
 }
@@ -764,37 +575,11 @@ func TestResolveIPAddresses_CloudflareDomain(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
-	ips := liveResolveIPs(t, r, "cloudflare.com")
+	ctx := testContext(t)
-	assert.NotEmpty(t, ips)
+	ips, err := r.ResolveIPAddresses(ctx, "cloudflare.com")
-}
+	require.NoError(t, err)
-
+	require.NotEmpty(t, ips)
 // TestResolveIPAddresses_NameserverIPv4AndIPv6 looks up the addresses of
 // one of cloudflare.com's nameservers, as a domain check does for each
 // nameserver. That name has A and AAAA records, so both kinds of address
 // come back.
 func TestResolveIPAddresses_NameserverIPv4AndIPv6(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
 	ns := findOneNSForDomain(t, r, "cloudflare.com")
 	ips := liveResolveIPs(t, r, ns)
 	var ipv4, ipv6 int
 	for _, ip := range ips {
 		parsed := net.ParseIP(ip)
 		require.NotNil(t, parsed, "should be valid IP: %s", ip)
 		if parsed.To4() != nil {
 			ipv4++
 		} else {
 			ipv6++
 		}
 	}
 	assert.Positive(t, ipv4, "no IPv4 address for %s: %v", ns, ips)
 	assert.Positive(t, ipv6, "no IPv6 address for %s: %v", ns, ips)
 }
 // ----------------------------------------------------------------
@@ -838,29 +623,6 @@ func TestQueryAllNameservers_ContextCanceled(t *testing.T) {
 	assert.Error(t, err)
 }
 // TestQueryEachNS_CanceledDuringQuery cancels the context while a
 // nameserver is being queried, as shutdown does. A lookup cut short
 // says nothing about the nameserver, so it must return an error, not a
 // failed response for it.
 func TestQueryEachNS_CanceledDuringQuery(t *testing.T) {
 	t.Parallel()
 	r := newTestResolver(t)
 	ctx, cancel := context.WithCancel(context.Background())
 	t.Cleanup(cancel)
 	// Finding the nameserver's address alone starts at the root
 	// servers and takes several round trips, so a cancel a few
 	// milliseconds in lands during the query.
 	time.AfterFunc(5*time.Millisecond, cancel)
 	results, err := r.QueryEachNS(
 		ctx, []string{"ns1.google.com."}, "google.com",
 	)
 	require.ErrorIs(t, err, resolver.ErrContextCanceled)
 	assert.Nil(t, results)
 }
 // ----------------------------------------------------------------
 // Timeout tests
 // ----------------------------------------------------------------
@@ -868,18 +630,21 @@ func TestQueryEachNS_CanceledDuringQuery(t *testing.T) {
 func TestQueryNameserverIP_Timeout(t *testing.T) {
 	t.Parallel()
-	r := newTestResolver(t)
+	log := slog.New(slog.NewTextHandler(
 		os.Stderr,
 		&slog.HandlerOptions{Level: slog.LevelDebug},
 	))
 	r := resolver.NewFromLoggerWithClient(
 		log, &timeoutClient{},
 	)
 	// Nothing answers at 192.0.2.1, a documentation address. The
 	// resolver tries each query twice, and the first try gives up
 	// after two seconds. A deadline that ends during the first try
 	// makes the status vary from run to run between error and
 	// timeout, so the deadline must outlast the first try.
 	ctx, cancel := context.WithTimeout(
-		context.Background(), 3*time.Second,
+		context.Background(), 10*time.Second,
 	)
 	t.Cleanup(cancel)
 	// Query any IP — the client always returns a timeout error.
 	resp, err := r.QueryNameserverIP(
 		ctx, "unreachable.test.", "192.0.2.1",
 		"example.com",
@@ -890,81 +655,26 @@ func TestQueryNameserverIP_Timeout(t *testing.T) {
 	assert.NotEmpty(t, resp.Error)
 }
-// TestCollectIPs_NoNameserverAnswered takes the response of a
+// timeoutClient simulates DNS timeout errors for testing.
-// nameserver at 192.0.2.1, where nothing answers, as
+type timeoutClient struct{}
 // TestQueryNameserverIP_Timeout does. Addresses collected from
 // nameservers that all failed to answer are an error, not none.
 func TestCollectIPs_NoNameserverAnswered(t *testing.T) {
 	t.Parallel()
-	r := newTestResolver(t)
+func (c *timeoutClient) ExchangeContext(
-
+	_ context.Context,
-	// The deadline outlasts the first try, as in
+	_ *dns.Msg,
-	// TestQueryNameserverIP_Timeout.
+	_ string,
-	ctx, cancel := context.WithTimeout(
+) (*dns.Msg, time.Duration, error) {
-		context.Background(), 3*time.Second,
+	return nil, 0, &net.OpError{
-	)
+		Op:  "read",
-	t.Cleanup(cancel)
+		Net: "udp",
-
+		Err: &timeoutError{},
-	resp, err := r.QueryNameserverIP(
+	}
 		ctx, "unreachable.test.", "192.0.2.1",
 		"example.com",
 	)
 	require.NoError(t, err)
 	ips, _, err := resolver.CollectIPs(
 		map[string]*resolver.NameserverResponse{resp.Nameserver: resp},
 	)
 	require.ErrorIs(t, err, resolver.ErrNoNameserverAnswered)
 	assert.Empty(t, ips)
 }
-// TestCollectIPs_ReferralIsNoAnswer asks a root server about
+type timeoutError struct{}
 // example.com, which the root zone does not hold, so it only refers the
 // query to the com servers. That reply is no answer, as is a parent
 // zone's when every server of the name's own zone failed.
 func TestCollectIPs_ReferralIsNoAnswer(t *testing.T) {
 	t.Parallel()
-	r := newTestResolver(t)
+func (e *timeoutError) Error() string   { return "i/o timeout" }
-
+func (e *timeoutError) Timeout() bool   { return true }
-	var resp *resolver.NameserverResponse
+func (e *timeoutError) Temporary() bool { return true }
 	livednstest.Retry(
 		t,
 		"QueryNameserverIP(a.root-servers.net, example.com)",
 		func(ctx context.Context) error {
 			var err error
 			resp, err = r.QueryNameserverIP(
 				ctx, "a.root-servers.net.", "198.41.0.4",
 				"example.com",
 			)
 			if err != nil {
 				return err
 			}
 			// A timeout or a network error is no reply at all.
 			if resp.Status == resolver.StatusTimeout ||
 				strings.HasPrefix(resp.Error, "network error") {
 				return fmt.Errorf(
 					"%w: %s", livednstest.ErrNoAnswer, resp.Error,
 				)
 			}
 			return nil
 		},
 	)
 	assert.Equal(t, resolver.StatusError, resp.Status)
 	assert.Equal(t, "server returned a referral", resp.Error)
 	ips, _, err := resolver.CollectIPs(
 		map[string]*resolver.NameserverResponse{resp.Nameserver: resp},
 	)
 	require.ErrorIs(t, err, resolver.ErrNoNameserverAnswered)
 	assert.Empty(t, ips)
 }
 func TestResolveIPAddresses_ContextCanceled(t *testing.T) {
 	t.Parallel()
@@ -1,38 +0,0 @@
 package server
 import (
 	"net/http"
 	"time"
 	"github.com/go-chi/chi/v5"
 )
 // RequestTimeout exports the handler execution budget applied by
 // chimw.Timeout in SetupRoutes, so tests can assert the relationship
 // between it and the server's WriteTimeout.
 const RequestTimeout time.Duration = requestTimeout
 // SetListenPort overrides the port Run binds. A test uses it to hand
 // Run an unbindable port so ListenAndServe fails immediately and Run
 // returns after storing its http.Server.
 func SetListenPort(s *Server, port int) {
 	s.port = port
 }
 // HTTPServerOf returns the http.Server that Run built and stored, so a
 // test can inspect the timeouts the running server actually carries.
 func HTTPServerOf(s *Server) *http.Server {
 	return s.httpServer
 }
 // EnableSentry runs the Sentry setup that the start hook runs, without
 // starting the HTTP server.
 func EnableSentry(s *Server) error {
 	return s.enableSentry()
 }
 // RouterOf returns the router SetupRoutes built, so a test can add a
 // route that panics.
 func RouterOf(s *Server) *chi.Mux {
 	return s.router
 }
@@ -4,7 +4,6 @@ import (
 	"net/http"
 	"time"
 	sentryhttp "github.com/getsentry/sentry-go/http"
 	"github.com/go-chi/chi/v5"
 	chimw "github.com/go-chi/chi/v5/middleware"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -22,32 +21,15 @@ func (s *Server) SetupRoutes() {
 	// Global middleware
 	s.router.Use(chimw.Recoverer)
 	s.router.Use(chimw.RequestID)
 	s.router.Use(s.mw.SecurityHeaders())
 	s.router.Use(s.mw.Logging())
 	s.router.Use(s.mw.CORS())
 	s.router.Use(chimw.Timeout(requestTimeout))
 	// Report panics in handlers to Sentry when DNSWATCHER_SENTRY_DSN is
 	// set. Repanic passes each panic on to chimw.Recoverer above, which
 	// still answers the request.
 	if s.sentryEnabled {
 		sentryHandler := sentryhttp.New(sentryhttp.Options{
 			Repanic: true,
 		})
 		s.router.Use(sentryHandler.Handle)
 	}
 	// Public, unauthenticated, read-only routes, the only ones
 	// REPO_POLICIES.md allows wildcard CORS on. CORS is middleware of
 	// this whole router, not of a Group, so that it also answers
 	// OPTIONS preflight requests, which no route here registers.
 	public := chi.NewRouter()
 	public.Use(s.mw.CORS())
 	// Dashboard (read-only web UI)
-	public.Get("/", s.handlers.HandleDashboard())
+	s.router.Get("/", s.handlers.HandleDashboard())
 	// Static assets (embedded CSS/JS)
-	public.Mount(
+	s.router.Mount(
 		"/s",
 		http.StripPrefix(
 			"/s",
@@ -56,33 +38,27 @@ func (s *Server) SetupRoutes() {
 	)
 	// Health check (standard well-known path)
-	public.Get(
+	s.router.Get(
 		"/.well-known/healthcheck",
 		s.handlers.HandleHealthCheck(),
 	)
 	// Legacy health check (keep for backward compatibility)
-	public.Get("/health", s.handlers.HandleHealthCheck())
+	s.router.Get("/health", s.handlers.HandleHealthCheck())
 	// API v1 routes
-	public.Route("/api/v1", func(r chi.Router) {
+	s.router.Route("/api/v1", func(r chi.Router) {
 		r.Get("/status", s.handlers.HandleStatus())
 	})
-	s.router.Mount("/", public)
+	// Metrics endpoint (optional, with basic auth)
 	// Metrics endpoint (optional, with basic auth) and no CORS: a
 	// Prometheus scraper is not a browser. It is mounted rather than
 	// added with Get so that every method on /metrics, OPTIONS
 	// included, ends here instead of falling through to the public
 	// router and its CORS. The rate limit comes before Basic Auth, so
 	// failed logins count against it and a request over the limit
 	// never reaches the password check.
 	if s.params.Config.MetricsUsername != "" {
-		metrics := chi.NewRouter()
+		s.router.Group(func(r chi.Router) {
-		metrics.Use(s.mw.MetricsRateLimit())
+			r.Use(s.mw.MetricsAuth())
-		metrics.Use(s.mw.MetricsAuth())
+			r.Get(
-		metrics.Get("/", promhttp.Handler().ServeHTTP)
+				"/metrics",
-		s.router.Mount("/metrics", metrics)
+				promhttp.Handler().ServeHTTP,
 			)
 		})
 	}
 }
@@ -1,290 +0,0 @@
 package server_test
 import (
 	"net/http"
 	"net/http/httptest"
 	"testing"
 	"github.com/spf13/viper"
 	"sneak.berlin/go/dnswatcher/internal/server"
 )
 // Credentials for /metrics, which is only routed when a username is set.
 const (
 	metricsUsername = "scraper"
 	metricsPassword = "scrape-secret"
 )
 // The tests below set env vars and touch viper global state, so like
 // the config tests they cannot use t.Parallel.
 // routedServer builds the server with its routes set up, ready to serve
 // test requests. The caller must first configure viper.
 func routedServer(t *testing.T) *server.Server {
 	t.Helper()
 	srv := buildServer(t)
 	srv.SetupRoutes()
 	return srv
 }
 // crossOriginRequest builds a request as a browser sends it from a page
 // on another site.
 func crossOriginRequest(
 	t *testing.T,
 	method string,
 	target string,
 ) *http.Request {
 	t.Helper()
 	req := httptest.NewRequestWithContext(t.Context(), method, target, nil)
 	req.Header.Set("Origin", "https://example.net")
 	return req
 }
 // preflightRequest builds the OPTIONS request a browser sends before a
 // cross-origin request with the given method and request headers.
 func preflightRequest(
 	t *testing.T,
 	target string,
 	method string,
 	headers string,
 ) *http.Request {
 	t.Helper()
 	req := crossOriginRequest(t, http.MethodOptions, target)
 	req.Header.Set("Access-Control-Request-Method", method)
 	if headers != "" {
 		req.Header.Set("Access-Control-Request-Headers", headers)
 	}
 	return req
 }
 func serve(
 	srv *server.Server,
 	req *http.Request,
 ) *httptest.ResponseRecorder {
 	rec := httptest.NewRecorder()
 	srv.ServeHTTP(rec, req)
 	return rec
 }
 // publicPaths returns one path on each public route.
 func publicPaths() []string {
 	return []string{
 		"/",
 		"/s/css/tailwind.min.css",
 		"/api/v1/status",
 		"/health",
 		"/.well-known/healthcheck",
 	}
 }
 // TestPublicRoutesAllowAnyOrigin checks that every public route answers
 // a cross-origin GET with the CORS wildcard.
 func TestPublicRoutesAllowAnyOrigin(t *testing.T) {
 	viper.Reset()
 	t.Setenv("DNSWATCHER_TARGETS", "example.com")
 	t.Setenv("DNSWATCHER_METRICS_USERNAME", metricsUsername)
 	t.Setenv("DNSWATCHER_METRICS_PASSWORD", metricsPassword)
 	srv := routedServer(t)
 	for _, path := range publicPaths() {
 		rec := serve(srv, crossOriginRequest(t, http.MethodGet, path))
 		if rec.Code != http.StatusOK {
 			t.Errorf("GET %s: status = %d, want 200", path, rec.Code)
 		}
 		got := rec.Header().Get("Access-Control-Allow-Origin")
 		if got != "*" {
 			t.Errorf(
 				"GET %s: Access-Control-Allow-Origin = %q, want %q",
 				path, got, "*",
 			)
 		}
 	}
 }
 // TestMetricsHasNoCORS checks that no request to the Basic-Auth
 // protected /metrics, preflight included, gets a CORS header.
 func TestMetricsHasNoCORS(t *testing.T) {
 	viper.Reset()
 	t.Setenv("DNSWATCHER_TARGETS", "example.com")
 	t.Setenv("DNSWATCHER_METRICS_USERNAME", metricsUsername)
 	t.Setenv("DNSWATCHER_METRICS_PASSWORD", metricsPassword)
 	srv := routedServer(t)
 	authenticated := crossOriginRequest(t, http.MethodGet, "/metrics")
 	authenticated.SetBasicAuth(metricsUsername, metricsPassword)
 	tests := []struct {
 		name       string
 		req        *http.Request
 		wantStatus int
 	}{
 		{
 			"authenticated GET",
 			authenticated,
 			http.StatusOK,
 		},
 		{
 			"unauthenticated GET",
 			crossOriginRequest(t, http.MethodGet, "/metrics"),
 			http.StatusUnauthorized,
 		},
 		{
 			"preflight",
 			preflightRequest(t, "/metrics", http.MethodGet, ""),
 			http.StatusUnauthorized,
 		},
 	}
 	for _, tt := range tests {
 		rec := serve(srv, tt.req)
 		if rec.Code != tt.wantStatus {
 			t.Errorf(
 				"%s: status = %d, want %d",
 				tt.name, rec.Code, tt.wantStatus,
 			)
 		}
 		got := rec.Header().Get("Access-Control-Allow-Origin")
 		if got != "" {
 			t.Errorf(
 				"%s: Access-Control-Allow-Origin = %q, want none",
 				tt.name, got,
 			)
 		}
 	}
 }
 // TestPreflightAllowsOnlyWhatPublicRoutesServe checks what each public
 // route agrees to in a CORS preflight: GET, but not POST, PUT or
 // DELETE, which no route serves, and not the Authorization or
 // X-CSRF-Token headers, which no public route reads. It checks every
 // public route because one added with Get, such as /health, answers a
 // preflight only while CORS is middleware of a whole router; in a
 // Group, chi would answer it with 405 and no CORS headers.
 func TestPreflightAllowsOnlyWhatPublicRoutesServe(t *testing.T) {
 	viper.Reset()
 	t.Setenv("DNSWATCHER_TARGETS", "example.com")
 	t.Setenv("DNSWATCHER_METRICS_USERNAME", metricsUsername)
 	t.Setenv("DNSWATCHER_METRICS_PASSWORD", metricsPassword)
 	srv := routedServer(t)
 	tests := []struct {
 		method  string
 		headers string
 		allowed bool
 	}{
 		{http.MethodGet, "", true},
 		{http.MethodGet, "Content-Type", true},
 		{http.MethodPost, "", false},
 		{http.MethodPut, "", false},
 		{http.MethodDelete, "", false},
 		{http.MethodGet, "Authorization", false},
 		{http.MethodGet, "X-CSRF-Token", false},
 	}
 	for _, path := range publicPaths() {
 		for _, tt := range tests {
 			rec := serve(srv, preflightRequest(
 				t, path, tt.method, tt.headers,
 			))
 			want := ""
 			if tt.allowed {
 				want = tt.method
 			}
 			got := rec.Header().Get("Access-Control-Allow-Methods")
 			if got != want {
 				t.Errorf(
 					"preflight to %s for %s with headers %q: "+
 						"Access-Control-Allow-Methods = %q, want %q",
 					path, tt.method, tt.headers, got, want,
 				)
 			}
 		}
 	}
 }
 // metricsRequest builds a GET for /metrics from remoteAddr that logs
 // in with the given password.
 func metricsRequest(
 	t *testing.T,
 	remoteAddr string,
 	password string,
 ) *http.Request {
 	t.Helper()
 	req := httptest.NewRequestWithContext(
 		t.Context(), http.MethodGet, "/metrics", nil,
 	)
 	req.RemoteAddr = remoteAddr
 	req.SetBasicAuth(metricsUsername, password)
 	return req
 }
 // TestMetricsRateLimitComesBeforeAuth checks that failed logins to
 // /metrics count against the rate limit; that once an address is over
 // it, even the right password gets 429, with the same body as a wrong
 // one; and that another address still gets in.
 func TestMetricsRateLimitComesBeforeAuth(t *testing.T) {
 	viper.Reset()
 	t.Setenv("DNSWATCHER_TARGETS", "example.com")
 	t.Setenv("DNSWATCHER_METRICS_USERNAME", metricsUsername)
 	t.Setenv("DNSWATCHER_METRICS_PASSWORD", metricsPassword)
 	const (
 		guesser = "198.51.100.1:4000"
 		other   = "198.51.100.2:4000"
 		// Far more guesses than the rate limit allows.
 		maxGuesses = 1000
 	)
 	srv := routedServer(t)
 	var guess *httptest.ResponseRecorder
 	for range maxGuesses {
 		guess = serve(srv, metricsRequest(t, guesser, "wrong"))
 		if guess.Code != http.StatusUnauthorized {
 			break
 		}
 	}
 	if guess.Code != http.StatusTooManyRequests {
 		t.Fatalf("wrong password: status = %d, want 429", guess.Code)
 	}
 	right := serve(srv, metricsRequest(t, guesser, metricsPassword))
 	if right.Code != http.StatusTooManyRequests {
 		t.Errorf("right password: status = %d, want 429", right.Code)
 	}
 	if right.Body.String() != guess.Body.String() {
 		t.Errorf(
 			"429 body with right password = %q, with wrong one = %q",
 			right.Body.String(), guess.Body.String(),
 		)
 	}
 	rec := serve(srv, metricsRequest(t, other, metricsPassword))
 	if rec.Code != http.StatusOK {
 		t.Errorf("another address: status = %d, want 200", rec.Code)
 	}
 }
@@ -1,190 +0,0 @@
 package server_test
 import (
 	"io"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
 	"strings"
 	"sync"
 	"testing"
 	"time"
 	"github.com/getsentry/sentry-go"
 	"github.com/spf13/viper"
 	"go.uber.org/fx"
 	"sneak.berlin/go/dnswatcher/internal/server"
 )
 // The tests below set env vars and touch the global state of viper and
 // of Sentry, so they cannot use t.Parallel.
 // standInDelay is how long the Sentry stand-in takes to answer. It
 // records a report only then, so a report that Shutdown did not wait
 // for has not been recorded yet when Shutdown returns.
 const standInDelay = 100 * time.Millisecond
 // sentryStandIn is a local HTTP server in place of Sentry's, so that
 // nothing a test reports leaves the host. It keeps the body of every
 // request it receives.
 type sentryStandIn struct {
 	server *httptest.Server
 	mu     sync.Mutex
 	bodies []string
 }
 func newSentryStandIn(t *testing.T) *sentryStandIn {
 	t.Helper()
 	standIn := &sentryStandIn{}
 	standIn.server = httptest.NewServer(http.HandlerFunc(
 		func(_ http.ResponseWriter, r *http.Request) {
 			body, err := io.ReadAll(r.Body)
 			if err != nil {
 				t.Errorf("reading request to the Sentry stand-in: %v", err)
 			}
 			time.Sleep(standInDelay)
 			standIn.mu.Lock()
 			defer standIn.mu.Unlock()
 			standIn.bodies = append(standIn.bodies, string(body))
 		},
 	))
 	t.Cleanup(standIn.server.Close)
 	return standIn
 }
 // dsn returns a DSN that points Sentry at the stand-in.
 func (s *sentryStandIn) dsn(t *testing.T) string {
 	t.Helper()
 	dsn, err := url.Parse(s.server.URL)
 	if err != nil {
 		t.Fatalf("parsing the stand-in URL: %v", err)
 	}
 	dsn.User = url.User("public-key")
 	dsn.Path = "/1"
 	return dsn.String()
 }
 // received reports whether a request to the stand-in contained text.
 func (s *sentryStandIn) received(text string) bool {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 	for _, body := range s.bodies {
 		if strings.Contains(body, text) {
 			return true
 		}
 	}
 	return false
 }
 func TestSentryUnsetDoesNothing(t *testing.T) {
 	viper.Reset()
 	t.Setenv("DNSWATCHER_TARGETS", "example.com")
 	t.Setenv("DNSWATCHER_SENTRY_DSN", "")
 	srv := buildServer(t)
 	err := server.EnableSentry(srv)
 	if err != nil {
 		t.Fatalf("Sentry setup with no DSN: %v", err)
 	}
 	if sentry.CurrentHub().Client() != nil {
 		t.Error("Sentry was set up with no DSN configured")
 	}
 }
 // TestSentryReportsHandlerPanic checks that with a valid DSN a panic in
 // a handler is reported to Sentry, still reaches chimw.Recoverer, and
 // has been sent by the time Shutdown returns, and that nothing else is
 // sent to Sentry.
 func TestSentryReportsHandlerPanic(t *testing.T) {
 	standIn := newSentryStandIn(t)
 	viper.Reset()
 	t.Setenv("DNSWATCHER_TARGETS", "example.com")
 	t.Setenv("DNSWATCHER_SENTRY_DSN", standIn.dsn(t))
 	srv := buildServer(t)
 	err := server.EnableSentry(srv)
 	if err != nil {
 		t.Fatalf("Sentry setup with a valid DSN: %v", err)
 	}
 	// Sentry's client is global: close it so later tests find none.
 	t.Cleanup(func() {
 		sentry.CurrentHub().Client().Close()
 		sentry.CurrentHub().BindClient(nil)
 	})
 	const panicMessage = "handler panic in the Sentry test"
 	srv.SetupRoutes()
 	server.RouterOf(srv).Get(
 		"/panic",
 		func(http.ResponseWriter, *http.Request) {
 			panic(panicMessage)
 		},
 	)
 	// An ordinary request first: with client reports on, Sentry would
 	// add a count of its dropped transaction to the panic report.
 	serve(srv, httptest.NewRequestWithContext(
 		t.Context(), http.MethodGet, "/.well-known/healthcheck", nil,
 	))
 	rec := serve(srv, httptest.NewRequestWithContext(
 		t.Context(), http.MethodGet, "/panic", nil,
 	))
 	if rec.Code != http.StatusInternalServerError {
 		t.Errorf(
 			"status %d, want %d from the recoverer",
 			rec.Code, http.StatusInternalServerError,
 		)
 	}
 	err = srv.Shutdown(t.Context())
 	if err != nil {
 		t.Fatalf("Shutdown: %v", err)
 	}
 	if !standIn.received(panicMessage) {
 		t.Error("the panic had not been sent to Sentry when Shutdown returned")
 	}
 	if standIn.received("client_report") {
 		t.Error("Sentry was sent a client report, not only the panic")
 	}
 }
 func TestSentryInvalidDSNStopsStartup(t *testing.T) {
 	viper.Reset()
 	t.Setenv("DNSWATCHER_TARGETS", "example.com")
 	t.Setenv("DNSWATCHER_DATA_DIR", t.TempDir())
 	// Sentry cannot parse this: it has no public key before the host.
 	t.Setenv("DNSWATCHER_SENTRY_DSN", "https://sentry.test/1")
 	app := newServerApp(fx.Invoke(func(*server.Server) {}))
 	err := app.Start(t.Context())
 	if err == nil {
 		_ = app.Stop(t.Context())
 		t.Fatal("startup succeeded with an invalid DSN")
 	}
 	if !strings.Contains(err.Error(), "invalid DNSWATCHER_SENTRY_DSN") {
 		t.Errorf("startup error does not name the setting: %v", err)
 	}
 }
@@ -9,7 +9,6 @@ import (
 	"net/http"
 	"time"
 	"github.com/getsentry/sentry-go"
 	"github.com/go-chi/chi/v5"
 	"go.uber.org/fx"
@@ -34,68 +33,19 @@ type Params struct {
 // shutdownTimeout is how long to wait for graceful shutdown.
 const shutdownTimeout = 30 * time.Second
-// sentryFlushTimeout is how long shutdown waits for Sentry to send the
+// readHeaderTimeout is the max duration for reading request headers.
-// error reports it still holds.
+const readHeaderTimeout = 10 * time.Second
 const sentryFlushTimeout = 2 * time.Second
 // Socket-level timeouts for the HTTP server.
 //
 // These bound time spent on the connection itself and are a distinct
 // control from the per-request handler budget enforced by
 // chimw.Timeout(requestTimeout) in routes.go: that one cancels the
 // request context after requestTimeout but never touches the socket,
 // so without the values below a peer can hold a connection open
 // forever (slowloris, unreaped keep-alives).
 //
 // The one hard constraint between the two controls is
 // writeTimeout > requestTimeout. net/http arms the write deadline
 // once the request headers have been read, so on a plaintext
 // connection it covers handler execution AND the response flush. If
 // writeTimeout were <= requestTimeout the server would sever the
 // connection before a handler that legitimately consumed its full
 // budget could emit anything, making the 60s budget unreachable in
 // practice. The margin between them is the response-flush allowance.
 //
 // The only clients of this service are browsers loading the dashboard
 // and a Prometheus scraper; the values are sized for those.
 const (
 	// readHeaderTimeout is the max duration for reading request
 	// headers.
 	readHeaderTimeout = 10 * time.Second
 	// readTimeout bounds reading the entire request, headers plus
 	// body. Every route here is a GET with no body, so this only
 	// ever needs to cover headers; the extra 5s over
 	// readHeaderTimeout is slack, not a real allowance, and keeps a
 	// body dribbled one byte at a time from holding the read side
 	// open indefinitely.
 	readTimeout = 15 * time.Second
 	// writeTimeout must exceed the requestTimeout handler budget
 	// (60s) per the note above. The 15s difference is the allowance
 	// for flushing a completed response to a slow client.
 	writeTimeout = 75 * time.Second
 	// idleTimeout reaps keep-alive connections between requests. It
 	// is deliberately longer than the common Prometheus scrape
 	// intervals (15s/30s/60s) so the scraper reuses its connection
 	// rather than reconnecting every cycle, while a browser tab
 	// left open on the dashboard stops occupying a connection
 	// within two minutes of going quiet.
 	idleTimeout = 120 * time.Second
 )
 // Server is the HTTP server.
 type Server struct {
-	startupTime   time.Time
+	startupTime time.Time
-	port          int
+	port        int
-	sentryEnabled bool
+	log         *slog.Logger
-	log           *slog.Logger
+	router      *chi.Mux
-	router        *chi.Mux
+	httpServer  *http.Server
-	httpServer    *http.Server
+	params      Params
-	params        Params
+	mw          *middleware.Middleware
-	mw            *middleware.Middleware
+	handlers    *handlers.Handlers
 	handlers      *handlers.Handlers
 }
 // New creates a new Server instance.
@@ -114,12 +64,6 @@ func New(
 	lifecycle.Append(fx.Hook{
 		OnStart: func(_ context.Context) error {
 			srv.startupTime = time.Now()
 			err := srv.enableSentry()
 			if err != nil {
 				return err
 			}
 			go srv.Run()
 			return nil
@@ -132,29 +76,16 @@ func New(
 	return srv, nil
 }
 // newHTTPServer builds the listening http.Server with every
 // socket-level timeout set. All four are set deliberately: a zero
 // value in net/http means "no limit", not "some default".
 func newHTTPServer(
 	listenAddr string,
 	handler http.Handler,
 ) *http.Server {
 	return &http.Server{
 		Addr:              listenAddr,
 		Handler:           handler,
 		ReadTimeout:       readTimeout,
 		ReadHeaderTimeout: readHeaderTimeout,
 		WriteTimeout:      writeTimeout,
 		IdleTimeout:       idleTimeout,
 	}
 }
 // Run starts the HTTP server.
 func (s *Server) Run() {
 	s.SetupRoutes()
 	listenAddr := fmt.Sprintf(":%d", s.port)
-	s.httpServer = newHTTPServer(listenAddr, s)
+	s.httpServer = &http.Server{
 		Addr:              listenAddr,
 		Handler:           s,
 		ReadHeaderTimeout: readHeaderTimeout,
 	}
 	s.log.Info("http server starting", "addr", listenAddr)
@@ -164,11 +95,8 @@ func (s *Server) Run() {
 	}
 }
-// Shutdown gracefully shuts down the server, then sends the error
+// Shutdown gracefully shuts down the server.
 // reports Sentry still holds.
 func (s *Server) Shutdown(ctx context.Context) error {
 	defer s.flushSentry()
 	if s.httpServer == nil {
 		return nil
 	}
@@ -199,45 +127,3 @@ func (s *Server) ServeHTTP(
 ) {
 	s.router.ServeHTTP(writer, request)
 }
 // enableSentry turns on Sentry error reporting when
 // DNSWATCHER_SENTRY_DSN is set, and does nothing when it is not. A DSN
 // that Sentry cannot parse is an error, so that startup stops instead
 // of running without the error reporting the operator asked for.
 func (s *Server) enableSentry() error {
 	if s.params.Config.SentryDSN == "" {
 		return nil
 	}
 	err := sentry.Init(sentry.ClientOptions{
 		Dsn:     s.params.Config.SentryDSN,
 		Release: s.params.Globals.Appname + "-" + s.params.Globals.Version,
 		// Use the transport that queues each report as it is made. With
 		// the default one, Flush can return before sending a report made
 		// just before it, such as one from the last request at shutdown.
 		DisableTelemetryBuffer: true,
 		// Send panic reports only, not Sentry's counts of what it dropped,
 		// such as the transaction it starts for every request.
 		DisableClientReports: true,
 	})
 	if err != nil {
 		return fmt.Errorf("invalid DNSWATCHER_SENTRY_DSN: %w", err)
 	}
 	s.log.Info("sentry error reporting activated")
 	s.sentryEnabled = true
 	return nil
 }
 // flushSentry sends the error reports Sentry still holds, waiting at
 // most sentryFlushTimeout.
 func (s *Server) flushSentry() {
 	if !s.sentryEnabled {
 		return
 	}
 	if !sentry.Flush(sentryFlushTimeout) {
 		s.log.Warn("sentry flush timed out; some error reports were not sent")
 	}
 }
@@ -1,135 +0,0 @@
 package server_test
 import (
 	"testing"
 	"github.com/spf13/viper"
 	"go.uber.org/fx"
 	"sneak.berlin/go/dnswatcher/internal/config"
 	"sneak.berlin/go/dnswatcher/internal/globals"
 	"sneak.berlin/go/dnswatcher/internal/handlers"
 	"sneak.berlin/go/dnswatcher/internal/healthcheck"
 	"sneak.berlin/go/dnswatcher/internal/logger"
 	"sneak.berlin/go/dnswatcher/internal/middleware"
 	"sneak.berlin/go/dnswatcher/internal/notify"
 	"sneak.berlin/go/dnswatcher/internal/server"
 	"sneak.berlin/go/dnswatcher/internal/state"
 )
 // newServerApp builds an fx app holding a *server.Server wired exactly
 // as cmd/dnswatcher wires it, minus the watcher/resolver subtree that
 // would touch live DNS, plus the given option. config.New reads viper,
 // so the caller must first configure it, which is also why the caller
 // cannot run in parallel.
 func newServerApp(option fx.Option) *fx.App {
 	return fx.New(
 		fx.NopLogger,
 		fx.Provide(
 			globals.New,
 			logger.New,
 			config.New,
 			state.New,
 			healthcheck.New,
 			notify.New,
 			middleware.New,
 			handlers.New,
 			server.New,
 		),
 		option,
 	)
 }
 // buildServer builds the server without starting the app's lifecycle,
 // so no OnStart hook runs and nothing listens or resolves.
 func buildServer(t *testing.T) *server.Server {
 	t.Helper()
 	var srv *server.Server
 	app := newServerApp(fx.Populate(&srv))
 	err := app.Err()
 	if err != nil {
 		t.Fatalf("building server graph: %v", err)
 	}
 	return srv
 }
 // TestRunWiresSocketTimeouts pins that the http.Server the running
 // server actually serves — the one Run builds and hands to
 // ListenAndServe — carries every socket-level timeout, plus the two
 // relationships the values must satisfy.
 //
 // Run is driven to completion with an unbindable port: it builds and
 // stores s.httpServer, then ListenAndServe fails at once and Run
 // returns without ever listening. The assertions run in the same
 // goroutine after Run returns, so reading s.httpServer is free of any
 // data race. Nothing here measures elapsed time.
 //
 // ReadTimeout must be at least ReadHeaderTimeout. net/http reads the
 // headers under ReadHeaderTimeout, then sets the read deadline for the
 // rest of the request to ReadTimeout, counted from when it started
 // reading the request. If ReadTimeout were smaller, a request whose
 // headers arrived after ReadTimeout but within ReadHeaderTimeout would
 // get a read deadline that had already passed, so reading its body
 // would fail at once.
 func TestRunWiresSocketTimeouts(t *testing.T) {
 	// Sets an env var and touches viper global state, so like the
 	// config tests it cannot use t.Parallel.
 	viper.Reset()
 	t.Setenv("DNSWATCHER_TARGETS", "example.com")
 	srv := buildServer(t)
 	server.SetListenPort(srv, -1)
 	srv.Run()
 	hs := server.HTTPServerOf(srv)
 	if hs == nil {
 		t.Fatal("Run did not build an http.Server")
 	}
 	if hs.ReadTimeout <= 0 {
 		t.Errorf("ReadTimeout must be non-zero, got %v", hs.ReadTimeout)
 	}
 	if hs.ReadHeaderTimeout <= 0 {
 		t.Errorf(
 			"ReadHeaderTimeout must be non-zero, got %v",
 			hs.ReadHeaderTimeout,
 		)
 	}
 	if hs.WriteTimeout <= 0 {
 		t.Errorf("WriteTimeout must be non-zero, got %v", hs.WriteTimeout)
 	}
 	if hs.IdleTimeout <= 0 {
 		t.Errorf("IdleTimeout must be non-zero, got %v", hs.IdleTimeout)
 	}
 	if hs.WriteTimeout <= server.RequestTimeout {
 		t.Errorf(
 			"WriteTimeout (%v) must exceed handler budget (%v)",
 			hs.WriteTimeout,
 			server.RequestTimeout,
 		)
 	}
 	if hs.ReadTimeout < hs.ReadHeaderTimeout {
 		t.Errorf(
 			"ReadTimeout (%v) must be >= ReadHeaderTimeout (%v)",
 			hs.ReadTimeout,
 			hs.ReadHeaderTimeout,
 		)
 	}
 	if hs.Handler != srv {
 		t.Errorf(
 			"Run wired handler %T, want the *server.Server",
 			hs.Handler,
 		)
 	}
 }
@@ -1,23 +0,0 @@
 package state
 import (
 	"log/slog"
 	"sneak.berlin/go/dnswatcher/internal/config"
 )
 // NewForTestWithDataDir creates an empty State that saves to dataDir,
 // without the fx lifecycle.
 func NewForTestWithDataDir(dataDir string) *State {
 	return &State{
 		log: slog.Default(),
 		snapshot: &Snapshot{
 			Version:      stateVersion,
 			Domains:      make(map[string]*DomainState),
 			Hostnames:    make(map[string]*HostnameState),
 			Ports:        make(map[string]*PortState),
 			Certificates: make(map[string]*CertificateState),
 		},
 		config: &config.Config{DataDir: dataDir},
 	}
 }
@@ -35,38 +35,22 @@ type Params struct {
 }
 // DomainState holds the monitoring state for an apex domain.
 // NameserverAddresses holds the sorted addresses each nameserver's name
 // resolves to, by nameserver name. A state file written before it
 // existed loads with it nil.
 type DomainState struct {
-	Nameservers         []string            `json:"nameservers"`
+	Nameservers []string  `json:"nameservers"`
-	NameserverAddresses map[string][]string `json:"nameserverAddresses"`
+	LastChecked time.Time `json:"lastChecked"`
 	LastChecked         time.Time           `json:"lastChecked"`
 }
 // NameserverRecordState holds one NS's response for a hostname.
 // FailedTypes lists the record types whose query to the nameserver
 // failed on this check: Records holds for them the records saved by the
 // previous check, which are kept. UnknownTypes lists those of them whose
 // records the previous check did not know either, as when the
 // nameserver was new or failing then: Records holds nothing for them.
 type NameserverRecordState struct {
-	Records      map[string][]string `json:"records"`
+	Records     map[string][]string `json:"records"`
-	FailedTypes  []string            `json:"failedTypes,omitempty"`
+	Status      string              `json:"status"`
-	UnknownTypes []string            `json:"unknownTypes,omitempty"`
+	Error       string              `json:"error,omitempty"`
-	Status       string              `json:"status"`
+	LastChecked time.Time           `json:"lastChecked"`
 	Error        string              `json:"error,omitempty"`
 	LastChecked  time.Time           `json:"lastChecked"`
 }
 // HostnameState holds per-nameserver monitoring state for a hostname.
 // CNAMEAddresses holds the sorted addresses at the end of the name's
 // CNAME chain, found when its nameservers answered with a CNAME and no
 // address; it is empty otherwise. It is nil when they are not known: a
 // state file written before it existed loads with it nil.
 type HostnameState struct {
 	RecordsByNameserver map[string]*NameserverRecordState `json:"recordsByNameserver"`
 	CNAMEAddresses      []string                          `json:"cnameAddresses"`
 	LastChecked         time.Time                         `json:"lastChecked"`
 }
@@ -164,11 +148,6 @@ func New(
 	lifecycle.Append(fx.Hook{
 		OnStart: func(_ context.Context) error {
 			err := state.checkDataDirWritable()
 			if err != nil {
 				return err
 			}
 			return state.Load()
 		},
 		OnStop: func(_ context.Context) error {
@@ -366,27 +345,3 @@ func (s *State) GetCertificateState(
 	return cs, ok
 }
 // checkDataDirWritable creates the data directory if needed, then writes
 // and removes the temp file that Save uses. It runs at startup so that an
 // unwritable directory stops the process, instead of the process running
 // with every save failing and only logged.
 func (s *State) checkDataDirWritable() error {
 	dir := s.config.DataDir
 	tmpPath := s.config.StatePath() + ".tmp"
 	err := os.MkdirAll(dir, dirPermissions)
 	if err == nil {
 		err = os.WriteFile(tmpPath, nil, filePermissions)
 	}
 	if err == nil {
 		err = os.Remove(tmpPath)
 	}
 	if err != nil {
 		return fmt.Errorf("data directory %s is not writable: %w", dir, err)
 	}
 	return nil
 }
@@ -4,17 +4,10 @@ import (
 	"encoding/json"
 	"os"
 	"path/filepath"
 	"reflect"
 	"strings"
 	"sync"
 	"testing"
 	"time"
 	"go.uber.org/fx/fxtest"
 	"sneak.berlin/go/dnswatcher/internal/config"
 	"sneak.berlin/go/dnswatcher/internal/globals"
 	"sneak.berlin/go/dnswatcher/internal/logger"
 	"sneak.berlin/go/dnswatcher/internal/state"
 )
@@ -38,10 +31,6 @@ func populateState(t *testing.T, s *state.State) {
 	s.SetDomainState("example.com", &state.DomainState{
 		Nameservers: []string{testNS1, testNS2},
 		NameserverAddresses: map[string][]string{
 			testNS1: {testIP, testIPv4},
 			testNS2: {testIPv4},
 		},
 		LastChecked: now,
 	})
@@ -128,153 +117,6 @@ func TestSaveLoadRoundTrip_Domains(t *testing.T) {
 	if len(dom.Nameservers) != 2 {
 		t.Errorf("expected 2 nameservers, got %d", len(dom.Nameservers))
 	}
 	want := map[string][]string{
 		testNS1: {testIP, testIPv4},
 		testNS2: {testIPv4},
 	}
 	if !reflect.DeepEqual(dom.NameserverAddresses, want) {
 		t.Errorf(
 			"nameserver addresses: got %v, want %v",
 			dom.NameserverAddresses, want,
 		)
 	}
 }
 // TestLoadStateFromBeforeNameserverAddresses loads a state file written
 // before nameserver addresses were saved.
 func TestLoadStateFromBeforeNameserverAddresses(t *testing.T) {
 	t.Parallel()
 	dir := t.TempDir()
 	data := []byte(`{
 		"version": 1,
 		"lastUpdated": "2026-02-19T12:00:00Z",
 		"domains": {
 			"example.com": {
 				"nameservers": ["ns1.example.com.", "ns2.example.com."],
 				"lastChecked": "2026-02-19T12:00:00Z"
 			}
 		}
 	}`)
 	err := os.WriteFile(filepath.Join(dir, "state.json"), data, 0o600)
 	if err != nil {
 		t.Fatalf("writing state file: %v", err)
 	}
 	s := state.NewForTestWithDataDir(dir)
 	err = s.Load()
 	if err != nil {
 		t.Fatalf("Load() error: %v", err)
 	}
 	dom, ok := s.GetDomainState("example.com")
 	if !ok {
 		t.Fatal("missing domain example.com")
 	}
 	if !reflect.DeepEqual(dom.Nameservers, []string{testNS1, testNS2}) {
 		t.Errorf("nameservers: got %v", dom.Nameservers)
 	}
 	if dom.NameserverAddresses != nil {
 		t.Errorf(
 			"nameserver addresses: got %v, want none",
 			dom.NameserverAddresses,
 		)
 	}
 }
 // TestSaveLoadRoundTrip_CNAMEAddresses checks that no addresses at the
 // end of a hostname's CNAME chain load as an empty list, and addresses
 // that are not known load as nil: the watcher tells the two apart.
 func TestSaveLoadRoundTrip_CNAMEAddresses(t *testing.T) {
 	t.Parallel()
 	dir := t.TempDir()
 	s := state.NewForTestWithDataDir(dir)
 	want := map[string][]string{
 		"cname.example.com":     {testIP},
 		"none.example.com":      {},
 		"not-known.example.com": nil,
 	}
 	for name, addresses := range want {
 		s.SetHostnameState(name, &state.HostnameState{
 			CNAMEAddresses: addresses,
 		})
 	}
 	err := s.Save()
 	if err != nil {
 		t.Fatalf("Save() error: %v", err)
 	}
 	loaded := state.NewForTestWithDataDir(dir)
 	err = loaded.Load()
 	if err != nil {
 		t.Fatalf("Load() error: %v", err)
 	}
 	for name, addresses := range want {
 		hs, ok := loaded.GetHostnameState(name)
 		if !ok {
 			t.Fatalf("missing hostname %s", name)
 		}
 		if !reflect.DeepEqual(hs.CNAMEAddresses, addresses) {
 			t.Errorf(
 				"%s: loaded %#v, want %#v",
 				name, hs.CNAMEAddresses, addresses,
 			)
 		}
 	}
 }
 // TestLoadStateFromBeforeCNAMEAddresses loads a state file written
 // before the addresses at the end of a hostname's CNAME chain were
 // saved. They load as not known (nil), not as none.
 func TestLoadStateFromBeforeCNAMEAddresses(t *testing.T) {
 	t.Parallel()
 	dir := t.TempDir()
 	data := []byte(`{
 		"version": 1,
 		"lastUpdated": "2026-02-19T12:00:00Z",
 		"hostnames": {
 			"www.example.com": {
 				"recordsByNameserver": {},
 				"lastChecked": "2026-02-19T12:00:00Z"
 			}
 		}
 	}`)
 	err := os.WriteFile(filepath.Join(dir, "state.json"), data, 0o600)
 	if err != nil {
 		t.Fatalf("writing state file: %v", err)
 	}
 	s := state.NewForTestWithDataDir(dir)
 	err = s.Load()
 	if err != nil {
 		t.Fatalf("Load() error: %v", err)
 	}
 	hs, ok := s.GetHostnameState(testHostname)
 	if !ok {
 		t.Fatal("missing hostname " + testHostname)
 	}
 	if hs.CNAMEAddresses != nil {
 		t.Errorf("CNAME addresses: got %#v, want nil", hs.CNAMEAddresses)
 	}
 }
 // TestSaveLoadRoundTrip_Hostnames verifies hostname data survives a save/load cycle.
@@ -651,107 +493,6 @@ func TestSaveWritePermissionError(t *testing.T) {
 	}
 }
 // startState builds a State through the real constructor and runs its
 // startup hook against dataDir, returning the startup error.
 func startState(t *testing.T, dataDir string) error {
 	t.Helper()
 	g, err := globals.New(nil)
 	if err != nil {
 		t.Fatalf("globals.New: %v", err)
 	}
 	log, err := logger.New(nil, logger.Params{Globals: g})
 	if err != nil {
 		t.Fatalf("logger.New: %v", err)
 	}
 	lifecycle := fxtest.NewLifecycle(t)
 	_, err = state.New(lifecycle, state.Params{
 		Logger: log,
 		Config: &config.Config{DataDir: dataDir},
 	})
 	if err != nil {
 		t.Fatalf("state.New: %v", err)
 	}
 	return lifecycle.Start(t.Context())
 }
 // TestStartupFailsWhenDataDirNotWritable verifies that startup stops
 // with an error naming the data directory when it cannot be written.
 // The directory's parent is a regular file, which also fails as root.
 func TestStartupFailsWhenDataDirNotWritable(t *testing.T) {
 	t.Parallel()
 	parent := filepath.Join(t.TempDir(), "file")
 	err := os.WriteFile(parent, nil, 0o600)
 	if err != nil {
 		t.Fatalf("writing file: %v", err)
 	}
 	dataDir := filepath.Join(parent, "data")
 	err = startState(t, dataDir)
 	if err == nil {
 		t.Fatal("startup should fail when the data directory is not writable")
 	}
 	want := "data directory " + dataDir + " is not writable"
 	if !strings.Contains(err.Error(), want) {
 		t.Errorf("startup error %q does not contain %q", err, want)
 	}
 }
 // TestStartupFailsWhenExistingDataDirNotWritable verifies that startup
 // stops when the data directory exists but the temp file that saving uses
 // cannot be written in it. A directory sitting at the temp file's path
 // makes that write fail, which also holds as root.
 func TestStartupFailsWhenExistingDataDirNotWritable(t *testing.T) {
 	t.Parallel()
 	dataDir := t.TempDir()
 	err := os.Mkdir(filepath.Join(dataDir, "state.json.tmp"), 0o700)
 	if err != nil {
 		t.Fatalf("creating directory: %v", err)
 	}
 	err = startState(t, dataDir)
 	if err == nil {
 		t.Fatal("startup should fail when the data directory is not writable")
 	}
 	want := "data directory " + dataDir + " is not writable"
 	if !strings.Contains(err.Error(), want) {
 		t.Errorf("startup error %q does not contain %q", err, want)
 	}
 }
 // TestStartupCreatesDataDir verifies that startup creates a missing
 // data directory and leaves nothing behind in it.
 func TestStartupCreatesDataDir(t *testing.T) {
 	t.Parallel()
 	dataDir := filepath.Join(t.TempDir(), "data")
 	err := startState(t, dataDir)
 	if err != nil {
 		t.Fatalf("startup error: %v", err)
 	}
 	entries, err := os.ReadDir(dataDir)
 	if err != nil {
 		t.Fatalf("reading data directory: %v", err)
 	}
 	if len(entries) != 0 {
 		t.Errorf("startup left %d entries in the data directory", len(entries))
 	}
 }
 // TestPortStateUnmarshalJSON_NewFormat verifies deserialization of the
 // current multi-hostname format.
 func TestPortStateUnmarshalJSON_NewFormat(t *testing.T) {
@@ -891,7 +632,7 @@ func TestPortStateUnmarshalJSON_BothFormats(t *testing.T) {
 func TestGetSnapshot_ReturnsCopy(t *testing.T) {
 	t.Parallel()
-	s := state.NewForTestWithDataDir(t.TempDir())
+	s := state.NewForTest()
 	populateState(t, s)
@@ -913,7 +654,7 @@ func TestGetSnapshot_ReturnsCopy(t *testing.T) {
 func TestDomainState_GetSet(t *testing.T) {
 	t.Parallel()
-	s := state.NewForTestWithDataDir(t.TempDir())
+	s := state.NewForTest()
 	// Get on missing key returns false.
 	_, ok := s.GetDomainState("nonexistent.com")
@@ -964,7 +705,7 @@ func TestDomainState_GetSet(t *testing.T) {
 func TestHostnameState_GetSet(t *testing.T) {
 	t.Parallel()
-	s := state.NewForTestWithDataDir(t.TempDir())
+	s := state.NewForTest()
 	_, ok := s.GetHostnameState("missing.example.com")
 	if ok {
@@ -1009,7 +750,7 @@ func TestHostnameState_GetSet(t *testing.T) {
 func TestPortState_GetSetDelete(t *testing.T) {
 	t.Parallel()
-	s := state.NewForTestWithDataDir(t.TempDir())
+	s := state.NewForTest()
 	_, ok := s.GetPortState("1.2.3.4:80")
 	if ok {
@@ -1047,7 +788,7 @@ func TestPortState_GetSetDelete(t *testing.T) {
 func TestGetAllPortKeys(t *testing.T) {
 	t.Parallel()
-	s := state.NewForTestWithDataDir(t.TempDir())
+	s := state.NewForTest()
 	keys := s.GetAllPortKeys()
 	if len(keys) != 0 {
@@ -1089,7 +830,7 @@ func TestGetAllPortKeys(t *testing.T) {
 func TestCertificateState_GetSet(t *testing.T) {
 	t.Parallel()
-	s := state.NewForTestWithDataDir(t.TempDir())
+	s := state.NewForTest()
 	_, ok := s.GetCertificateState("1.2.3.4:443:www.example.com")
 	if ok {
@@ -1310,7 +1051,7 @@ func TestLoadPreservesExistingStateOnMissingFile(t *testing.T) {
 func TestConcurrentGetSet(t *testing.T) {
 	t.Parallel()
-	s := state.NewForTestWithDataDir(t.TempDir())
+	s := state.NewForTest()
 	const goroutines = 20
@@ -1520,6 +1261,35 @@ func TestMultipleSavesOverwrite(t *testing.T) {
 	}
 }
 // TestNewForTest verifies the test helper creates a valid empty state.
 func TestNewForTest(t *testing.T) {
 	t.Parallel()
 	s := state.NewForTest()
 	snap := s.GetSnapshot()
 	if snap.Version != 1 {
 		t.Errorf("version: got %d, want 1", snap.Version)
 	}
 	if snap.Domains == nil {
 		t.Error("Domains map should be initialized")
 	}
 	if snap.Hostnames == nil {
 		t.Error("Hostnames map should be initialized")
 	}
 	if snap.Ports == nil {
 		t.Error("Ports map should be initialized")
 	}
 	if snap.Certificates == nil {
 		t.Error("Certificates map should be initialized")
 	}
 }
 // TestSaveFilePermissions verifies the saved file has restricted permissions.
 func TestSaveFilePermissions(t *testing.T) {
 	t.Parallel()
@@ -0,0 +1,38 @@
 package state
 import (
 	"log/slog"
 	"sneak.berlin/go/dnswatcher/internal/config"
 )
 // NewForTest creates a State for unit testing with no persistence.
 func NewForTest() *State {
 	return &State{
 		log: slog.Default(),
 		snapshot: &Snapshot{
 			Version:      stateVersion,
 			Domains:      make(map[string]*DomainState),
 			Hostnames:    make(map[string]*HostnameState),
 			Ports:        make(map[string]*PortState),
 			Certificates: make(map[string]*CertificateState),
 		},
 		config: &config.Config{DataDir: ""},
 	}
 }
 // NewForTestWithDataDir creates a State backed by the given directory
 // for tests that need file persistence.
 func NewForTestWithDataDir(dataDir string) *State {
 	return &State{
 		log: slog.Default(),
 		snapshot: &Snapshot{
 			Version:      stateVersion,
 			Domains:      make(map[string]*DomainState),
 			Hostnames:    make(map[string]*HostnameState),
 			Ports:        make(map[string]*PortState),
 			Certificates: make(map[string]*CertificateState),
 		},
 		config: &config.Config{DataDir: dataDir},
 	}
 }
@@ -1,81 +0,0 @@
 package watcher_test
 import (
 	"context"
 	"log/slog"
 	"reflect"
 	"testing"
 	"sneak.berlin/go/dnswatcher/internal/portcheck"
 	"sneak.berlin/go/dnswatcher/internal/resolver"
 	"sneak.berlin/go/dnswatcher/internal/state"
 	"sneak.berlin/go/dnswatcher/internal/tlscheck"
 	"sneak.berlin/go/dnswatcher/internal/watcher"
 )
 // TestCancelledCheckSavesNothing runs a check with its context already
 // cancelled, which is how the rest of a check runs once shutdown cuts it
 // short. The real resolver drops the DNS lookup without sending a query,
 // and the real port and TLS checkers fail without connecting. The port
 // and certificate state the last check saved must stay as it was, and
 // nothing may be notified.
 func TestCancelledCheckSavesNothing(t *testing.T) {
 	t.Parallel()
 	cfg := defaultTestConfig(t)
 	cfg.Hostnames = []string{host}
 	// newTestWatcher's watcher has stand-in checkers. This one, on the
 	// same state and notifier, has the real ones.
 	_, deps := newTestWatcher(t, cfg)
 	w := watcher.NewForTest(
 		cfg,
 		deps.state,
 		resolver.NewFromLogger(slog.Default()),
 		portcheck.NewStandalone(),
 		tlscheck.NewStandalone(),
 		deps.notifier,
 	)
 	// The last check found host at a local address, with both ports
 	// open and a good certificate.
 	const localIP = "127.0.0.1"
 	deps.state.SetHostnameState(host, hostnameState(
 		map[string]map[string][]string{nsA: {"A": {localIP}}},
 	))
 	ports := map[string]*state.PortState{
 		localIP + ":80":  {Open: true, Hostnames: []string{host}},
 		localIP + ":443": {Open: true, Hostnames: []string{host}},
 	}
 	for key, ps := range ports {
 		deps.state.SetPortState(key, ps)
 	}
 	certKey := localIP + ":443:" + host
 	cert := &state.CertificateState{CommonName: host, Status: "ok"}
 	deps.state.SetCertificateState(certKey, cert)
 	ctx, cancel := context.WithCancel(t.Context())
 	cancel()
 	w.RunOnce(ctx)
 	for key, want := range ports {
 		got, _ := deps.state.GetPortState(key)
 		if !reflect.DeepEqual(got, want) {
 			t.Errorf("port %s saved as %+v, want %+v", key, got, want)
 		}
 	}
 	got, _ := deps.state.GetCertificateState(certKey)
 	if !reflect.DeepEqual(got, cert) {
 		t.Errorf("certificate saved as %+v, want %+v", got, cert)
 	}
 	notifications := deps.notifier.getNotifications()
 	if len(notifications) != 0 {
 		t.Errorf("sent %v, want no notifications", notifications)
 	}
 }
@@ -1,372 +0,0 @@
 package watcher_test
 import (
 	"context"
 	"log/slog"
 	"slices"
 	"testing"
 	"sneak.berlin/go/dnswatcher/internal/livednstest"
 	"sneak.berlin/go/dnswatcher/internal/resolver"
 	"sneak.berlin/go/dnswatcher/internal/state"
 	"sneak.berlin/go/dnswatcher/internal/watcher"
 )
 // TestCNAMEIntoAnotherZonePortAndTLSChecks runs the port and TLS
 // checks on hostname state built here: the name's nameserver answered
 // with a CNAME into another zone, and following it found ip1. Both
 // checks must use ip1. They look nothing up, so the watcher has no
 // resolver.
 func TestCNAMEIntoAnotherZonePortAndTLSChecks(t *testing.T) {
 	t.Parallel()
 	cfg := defaultTestConfig(t)
 	cfg.Hostnames = []string{host}
 	deps := newTestDeps(t, cfg)
 	w := watcher.NewForTest(
 		cfg, deps.state, nil,
 		deps.portChecker, deps.tlsChecker, deps.notifier,
 	)
 	deps.state.SetHostnameState(host, cnameState(ip1))
 	w.CheckAllPorts(t.Context())
 	w.RunTLSChecks(t.Context())
 	snap := deps.state.GetSnapshot()
 	ps, ok := snap.Ports[ip1+":443"]
 	if !ok || !slices.Contains(ps.Hostnames, host) {
 		t.Errorf("no port state for %s at %s:443", host, ip1)
 	}
 	certKey := ip1 + ":443:" + host
 	if _, ok := snap.Certificates[certKey]; !ok {
 		t.Errorf("no certificate state %s", certKey)
 	}
 }
 // TestCNAMEThatCannotBeFollowedKeepsPrevious runs a check of a name, not
 // the watcher's first, from the point where its records have been looked
 // up: they hold a CNAME to a target under .invalid, whose lookup fails.
 // The previous check found the same records, and oldIP at the end of the
 // CNAME. The check must keep oldIP and send nothing.
 func TestCNAMEThatCannotBeFollowedKeepsPrevious(t *testing.T) {
 	t.Parallel()
 	w, deps := newTestWatcher(t, defaultTestConfig(t))
 	w.SetFirstRun(false)
 	records := map[string]map[string][]string{
 		nsA: cnameTo("target.example.invalid."),
 	}
 	prev := hostnameState(records)
 	prev.CNAMEAddresses = []string{oldIP}
 	deps.state.SetHostnameState(host, prev)
 	// The result is the same whether or not live DNS answers, so the
 	// lookup is not retried.
 	_ = livednstest.Run(func(ctx context.Context) error {
 		w.UpdateHostnameState(ctx, host, hostnameState(records))
 		return nil
 	})
 	hs, _ := deps.state.GetHostnameState(host)
 	if !slices.Equal(hs.CNAMEAddresses, prev.CNAMEAddresses) {
 		t.Errorf(
 			"saved %v, want %v",
 			hs.CNAMEAddresses, prev.CNAMEAddresses,
 		)
 	}
 	notifications := deps.notifier.getNotifications()
 	if len(notifications) != 0 {
 		t.Errorf("sent %v, want no notifications", notifications)
 	}
 }
 // followLive follows in live DNS the CNAMEs in a name's records, built
 // from records, and returns the addresses saved for the name. The
 // previous check saved oldIP, which is kept when a target cannot be
 // followed; that is retried. The tests point CNAMEs only at names in
 // zones with two nameservers, to keep queries few (see the top of
 // watcher_test.go).
 func followLive(
 	t *testing.T,
 	records map[string]map[string][]string,
 ) []string {
 	t.Helper()
 	w := watcher.NewForTest(
 		nil, nil, resolver.NewFromLogger(slog.Default()), nil, nil, nil,
 	)
 	prev := cnameState(oldIP)
 	var current *state.HostnameState
 	livednstest.Retry(t, "following CNAMEs", func(ctx context.Context) error {
 		current = hostnameState(records)
 		w.ResolveCNAMEAddresses(ctx, host, current, prev)
 		if slices.Equal(current.CNAMEAddresses, prev.CNAMEAddresses) {
 			return livednstest.ErrNoAnswer
 		}
 		return nil
 	})
 	return current.CNAMEAddresses
 }
 // TestCNAMEAddressesOfEveryTarget gives a name's two nameservers
 // different CNAME targets, as when a secondary still serves an old one.
 // The addresses at the end of both are saved, whichever answer is read
 // first: one.one.one.one has 1.1.1.1, and dns.adguard-dns.com has
 // 94.140.14.14.
 func TestCNAMEAddressesOfEveryTarget(t *testing.T) {
 	t.Parallel()
 	found := followLive(t, map[string]map[string][]string{
 		nsA: cnameTo("one.one.one.one."),
 		nsB: cnameTo("dns.adguard-dns.com."),
 	})
 	for _, ip := range []string{"1.1.1.1", "94.140.14.14"} {
 		if !slices.Contains(found, ip) {
 			t.Errorf("saved %v, want %s among them", found, ip)
 		}
 	}
 }
 // TestCNAMEChainEndingInNoAddressSavesEmptyList follows a CNAME to a
 // name live DNS answers with NXDOMAIN. An empty list is saved, not nil,
 // which would mean the addresses are not known.
 func TestCNAMEChainEndingInNoAddressSavesEmptyList(t *testing.T) {
 	t.Parallel()
 	found := followLive(t, map[string]map[string][]string{
 		nsA: cnameTo("this-surely-does-not-exist-xyz.example.org."),
 	})
 	if found == nil || len(found) != 0 {
 		t.Errorf("saved %#v, want an empty list", found)
 	}
 }
 // TestCNAMEBesideAnAddressNotFollowed gives one nameserver of a name an
 // address and another a CNAME. The CNAME is not followed: an empty list
 // is saved, not nil, and nothing is looked up, the watcher having no
 // resolver.
 func TestCNAMEBesideAnAddressNotFollowed(t *testing.T) {
 	t.Parallel()
 	w := watcher.NewForTest(nil, nil, nil, nil, nil, nil)
 	current := hostnameState(map[string]map[string][]string{
 		nsA: {"A": {ip1}},
 		nsB: cnameTo("target.example.org."),
 	})
 	w.ResolveCNAMEAddresses(t.Context(), host, current, nil)
 	if current.CNAMEAddresses == nil || len(current.CNAMEAddresses) != 0 {
 		t.Errorf("saved %#v, want an empty list", current.CNAMEAddresses)
 	}
 }
 // TestCNAMEWhoseNameserversAllFailedKeepsPrevious checks a name none of
 // whose nameservers answered. The addresses the previous check saved
 // from following its CNAME are kept, and nothing is looked up: the
 // watcher has no resolver.
 func TestCNAMEWhoseNameserversAllFailedKeepsPrevious(t *testing.T) {
 	t.Parallel()
 	w := watcher.NewForTest(nil, nil, nil, nil, nil, nil)
 	current := saved(map[string]*state.NameserverRecordState{
 		nsA: failed(), nsB: failed(),
 	})
 	prev := cnameState(oldIP)
 	w.ResolveCNAMEAddresses(t.Context(), host, current, prev)
 	if !slices.Equal(current.CNAMEAddresses, prev.CNAMEAddresses) {
 		t.Errorf(
 			"saved %v, want %v",
 			current.CNAMEAddresses, prev.CNAMEAddresses,
 		)
 	}
 }
 // TestCNAMEWhoseAddressQueryFailedKeepsPrevious checks a name whose
 // nameserver answered, but whose query for A, AAAA or CNAME failed with
 // nothing kept for it. That is not an answer with no address: the
 // addresses the previous check saved from following its CNAME are kept,
 // and nothing is looked up, the watcher having no resolver.
 func TestCNAMEWhoseAddressQueryFailedKeepsPrevious(t *testing.T) {
 	t.Parallel()
 	for _, rtype := range []string{"A", "AAAA", "CNAME"} {
 		t.Run(rtype, func(t *testing.T) {
 			t.Parallel()
 			w := watcher.NewForTest(nil, nil, nil, nil, nil, nil)
 			current := saved(map[string]*state.NameserverRecordState{
 				nsA: {
 					Records:      map[string][]string{},
 					FailedTypes:  []string{rtype},
 					UnknownTypes: []string{rtype},
 					Status:       "ok",
 				},
 			})
 			prev := cnameState(oldIP)
 			w.ResolveCNAMEAddresses(t.Context(), host, current, prev)
 			if !slices.Equal(current.CNAMEAddresses, prev.CNAMEAddresses) {
 				t.Errorf(
 					"saved %v, want %v",
 					current.CNAMEAddresses, prev.CNAMEAddresses,
 				)
 			}
 		})
 	}
 }
 // cnameTo builds the records of a nameserver that answered with a CNAME
 // to target and no address.
 func cnameTo(target string) map[string][]string {
 	return map[string][]string{"CNAME": {target}}
 }
 // cnameState builds the state a check leaves behind for a name whose
 // nameserver answered with a CNAME and no address, when following the
 // CNAME found these addresses, which may be none.
 func cnameState(addresses ...string) *state.HostnameState {
 	hs := hostnameState(map[string]map[string][]string{
 		nsA: cnameTo("target.example.org."),
 	})
 	hs.CNAMEAddresses = append([]string{}, addresses...)
 	return hs
 }
 func TestCNAMEAddressChangeAlerts(t *testing.T) {
 	t.Parallel()
 	// A state file written before the addresses were saved loads with
 	// them nil.
 	olderStateFile := cnameState()
 	olderStateFile.CNAMEAddresses = nil
 	// Each case is the state saved by the previous check and by the
 	// current one. The name's records are the same in both.
 	tests := []struct {
 		name          string
 		prev, current *state.HostnameState
 		want          int
 	}{
 		{
 			"same addresses",
 			cnameState(ip1, ip2), cnameState(ip1, ip2), 0,
 		},
 		{
 			"same addresses in another order",
 			cnameState(ip2, ip1), cnameState(ip1, ip2), 0,
 		},
 		{
 			"address replaced",
 			cnameState(ip1), cnameState(ip2), 1,
 		},
 		{
 			"address added",
 			cnameState(ip1), cnameState(ip1, ip2), 1,
 		},
 		{
 			"no address at the end of the chain now",
 			cnameState(ip1), cnameState(), 1,
 		},
 		{
 			"addresses at the end of the chain again",
 			cnameState(), cnameState(ip1), 1,
 		},
 		{
 			"state file from before addresses were saved",
 			olderStateFile, cnameState(ip1), 0,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			notifier := &mockNotifier{}
 			w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
 			w.DetectHostnameChanges(t.Context(), host, tt.prev, tt.current)
 			got := len(notifier.getNotifications())
 			if got != tt.want {
 				t.Errorf("sent %d notifications, want %d", got, tt.want)
 			}
 		})
 	}
 }
 func TestCNAMEAddressChangeAlertNamesHostnameAndAddresses(t *testing.T) {
 	t.Parallel()
 	notifier := &mockNotifier{}
 	w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
 	w.DetectHostnameChanges(
 		t.Context(), host, cnameState(ip1), cnameState(ip2, ip3),
 	)
 	want := notification{
 		Title: "CNAME Address Change: " + host,
 		Message: "Hostname: " + host +
 			"\nOld: " + ip1 + "\nNew: " + ip2 + ", " + ip3,
 		Priority: "warning",
 	}
 	got := notifier.getNotifications()
 	if len(got) != 1 || got[0] != want {
 		t.Errorf("sent %v, want %v", got, want)
 	}
 }
 // TestNameMovedFromARecordsToCNAMEAlerts checks a name that answers
 // with an A record and then with a CNAME whose chain ends in ip2. The
 // second check is notified as a CNAME address change from no addresses,
 // beside the record change. Nothing is looked up: the watcher has no
 // resolver.
 func TestNameMovedFromARecordsToCNAMEAlerts(t *testing.T) {
 	t.Parallel()
 	notifier := &mockNotifier{}
 	w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
 	prev := hostnameState(map[string]map[string][]string{
 		nsA: {"A": {ip1}},
 	})
 	w.ResolveCNAMEAddresses(t.Context(), host, prev, nil)
 	w.DetectHostnameChanges(t.Context(), host, prev, cnameState(ip2))
 	title := "CNAME Address Change: " + host
 	message := "Hostname: " + host + "\nOld: \nNew: " + ip2
 	got := notifier.getNotifications()
 	if !slices.ContainsFunc(got, func(n notification) bool {
 		return n.Title == title && n.Message == message
 	}) {
 		t.Errorf("sent %v, want %q with %q among them", got, title, message)
 	}
 }
@@ -1,110 +0,0 @@
 package watcher
 import (
 	"context"
 	"log/slog"
 	"time"
 	"sneak.berlin/go/dnswatcher/internal/config"
 	"sneak.berlin/go/dnswatcher/internal/resolver"
 	"sneak.berlin/go/dnswatcher/internal/state"
 )
 // NewForTest creates a Watcher without fx for unit testing.
 func NewForTest(
 	cfg *config.Config,
 	st *state.State,
 	res DNSResolver,
 	pc PortChecker,
 	tc TLSChecker,
 	n Notifier,
 ) *Watcher {
 	return &Watcher{
 		log:       slog.Default(),
 		config:    cfg,
 		state:     st,
 		resolver:  res,
 		portCheck: pc,
 		tlsCheck:  tc,
 		notify:    n,
 		firstRun:  true,
 	}
 }
 // NewlyDisagreeingPairs exports newlyDisagreeingPairs for testing.
 func NewlyDisagreeingPairs(
 	prev, current *state.HostnameState,
 ) [][2]string {
 	return newlyDisagreeingPairs(prev, current)
 }
 // SetFirstRun sets whether the watcher is on its first check, in which
 // nothing is compared with the previous check. NewForTest's watcher is.
 func (w *Watcher) SetFirstRun(firstRun bool) {
 	w.firstRun = firstRun
 }
 // UpdateHostnameState exports updateHostnameState for testing.
 func (w *Watcher) UpdateHostnameState(
 	ctx context.Context,
 	hostname string,
 	newState *state.HostnameState,
 ) {
 	w.updateHostnameState(ctx, hostname, newState)
 }
 // DetectHostnameChanges exports detectHostnameChanges for testing.
 func (w *Watcher) DetectHostnameChanges(
 	ctx context.Context,
 	hostname string,
 	prev, current *state.HostnameState,
 ) {
 	w.detectHostnameChanges(ctx, hostname, prev, current)
 }
 // ResolveNameserverAddresses exports resolveNameserverAddresses for
 // testing.
 func (w *Watcher) ResolveNameserverAddresses(
 	ctx context.Context,
 	nameservers []string,
 	prev map[string][]string,
 ) map[string][]string {
 	return w.resolveNameserverAddresses(ctx, nameservers, prev)
 }
 // ResolveCNAMEAddresses exports resolveCNAMEAddresses for testing.
 func (w *Watcher) ResolveCNAMEAddresses(
 	ctx context.Context,
 	hostname string,
 	current, prev *state.HostnameState,
 ) {
 	w.resolveCNAMEAddresses(ctx, hostname, current, prev)
 }
 // DetectNSAddressChanges exports detectNSAddressChanges for testing.
 func (w *Watcher) DetectNSAddressChanges(
 	ctx context.Context,
 	domain string,
 	prev, current map[string][]string,
 ) {
 	w.detectNSAddressChanges(ctx, domain, prev, current)
 }
 // CheckAllPorts exports checkAllPorts for testing.
 func (w *Watcher) CheckAllPorts(ctx context.Context) {
 	w.checkAllPorts(ctx)
 }
 // RunTLSChecks exports runTLSChecks for testing.
 func (w *Watcher) RunTLSChecks(ctx context.Context) {
 	w.runTLSChecks(ctx)
 }
 // BuildHostnameState exports buildHostnameState for testing.
 func BuildHostnameState(
 	results map[string]*resolver.NameserverResponse,
 	prev *state.HostnameState,
 	now time.Time,
 ) *state.HostnameState {
 	return buildHostnameState(results, prev, now)
 }
@@ -1,364 +0,0 @@
 package watcher_test
 import (
 	"maps"
 	"slices"
 	"testing"
 	"time"
 	"sneak.berlin/go/dnswatcher/internal/resolver"
 	"sneak.berlin/go/dnswatcher/internal/state"
 	"sneak.berlin/go/dnswatcher/internal/watcher"
 )
 const (
 	// txt is the record type whose query fails in these tests.
 	txt  = "TXT"
 	spf1 = "v=spf1 -all"
 	spf2 = "v=spf1 include:example.net -all"
 )
 // response is a nameserver's response with these records, whose queries
 // for failedTypes failed.
 func response(
 	records map[string][]string,
 	failedTypes ...string,
 ) *resolver.NameserverResponse {
 	return &resolver.NameserverResponse{
 		Records:     records,
 		FailedTypes: failedTypes,
 		Status:      resolver.StatusOK,
 	}
 }
 // savedChecks saves the state of each check in turn from the
 // nameservers' responses, each from the state the check before saved.
 func savedChecks(
 	checks ...map[string]*resolver.NameserverResponse,
 ) []*state.HostnameState {
 	states := make([]*state.HostnameState, 0, len(checks))
 	var prev *state.HostnameState
 	for _, results := range checks {
 		prev = watcher.BuildHostnameState(results, prev, time.Now())
 		states = append(states, prev)
 	}
 	return states
 }
 // TestFailedTypeKeepsPreviousRecords saves a check in which nsA's query
 // for TXT failed, after previous checks of several kinds. TXT is always
 // saved in FailedTypes, and in UnknownTypes when there was nothing to
 // keep.
 func TestFailedTypeKeepsPreviousRecords(t *testing.T) {
 	t.Parallel()
 	aOnly := map[string][]string{"A": {ip1}}
 	withTXT := map[string][]string{"A": {ip1}, txt: {spf1}}
 	txtKept := &state.NameserverRecordState{
 		Records: withTXT, FailedTypes: []string{txt}, Status: "ok",
 	}
 	txtNotKnown := &state.NameserverRecordState{
 		Records:      aOnly,
 		FailedTypes:  []string{txt},
 		UnknownTypes: []string{txt},
 		Status:       "ok",
 	}
 	tests := []struct {
 		name        string
 		prev        *state.HostnameState
 		wantRecords map[string][]string
 		wantUnknown []string
 	}{
 		{
 			"previous TXT records are kept",
 			saved(map[string]*state.NameserverRecordState{nsA: answered(withTXT)}),
 			withTXT, nil,
 		},
 		{
 			"previous check had no TXT records",
 			saved(map[string]*state.NameserverRecordState{nsA: answered(aOnly)}),
 			aOnly, nil,
 		},
 		{
 			"TXT failed on the previous check, which kept its records",
 			saved(map[string]*state.NameserverRecordState{nsA: txtKept}),
 			withTXT, nil,
 		},
 		{"first check", nil, aOnly, []string{txt}},
 		{
 			"nameserver new on this check",
 			saved(map[string]*state.NameserverRecordState{nsB: answered(withTXT)}),
 			aOnly, []string{txt},
 		},
 		{
 			"nameserver failed on the previous check",
 			saved(map[string]*state.NameserverRecordState{nsA: failed()}),
 			aOnly, []string{txt},
 		},
 		{
 			"TXT failed on the previous check with nothing to keep",
 			saved(map[string]*state.NameserverRecordState{nsA: txtNotKnown}),
 			aOnly, []string{txt},
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			hs := watcher.BuildHostnameState(
 				map[string]*resolver.NameserverResponse{
 					nsA: response(map[string][]string{"A": {ip1}}, txt),
 				},
 				tt.prev, time.Now(),
 			)
 			got := hs.RecordsByNameserver[nsA]
 			if got.Status != "ok" ||
 				!maps.EqualFunc(got.Records, tt.wantRecords, slices.Equal) ||
 				!slices.Equal(got.FailedTypes, []string{txt}) ||
 				!slices.Equal(got.UnknownTypes, tt.wantUnknown) {
 				t.Errorf(
 					"saved status %q, records %v, failed types %v, "+
 						"unknown types %v; want ok, %v, [%s], %v",
 					got.Status, got.Records, got.FailedTypes,
 					got.UnknownTypes, tt.wantRecords, txt, tt.wantUnknown,
 				)
 			}
 		})
 	}
 }
 // TestFailedTypeAlerts saves the checks of each case in turn from the
 // nameservers' responses, the first being the state loaded at startup,
 // and counts the alerts sent. nsB's TXT query fails on one check, and
 // nothing changes.
 func TestFailedTypeAlerts(t *testing.T) {
 	t.Parallel()
 	records := map[string][]string{"A": {ip1}, txt: {spf1}}
 	aOnly := map[string][]string{"A": {ip1}}
 	bothAnswer := map[string]*resolver.NameserverResponse{
 		nsA: response(records), nsB: response(records),
 	}
 	bTXTFails := map[string]*resolver.NameserverResponse{
 		nsA: response(records), nsB: response(aOnly, txt),
 	}
 	onlyA := map[string]*resolver.NameserverResponse{
 		nsA: response(records),
 	}
 	bFails := map[string]*resolver.NameserverResponse{
 		nsA: response(records),
 		nsB: {
 			Records: map[string][]string{},
 			Status:  resolver.StatusTimeout,
 			Error:   "all queries timed out",
 		},
 	}
 	tests := []struct {
 		name   string
 		checks []map[string]*resolver.NameserverResponse
 		want   alertCounts
 	}{
 		{
 			"type failing at one nameserver alerts nothing, nor its next answer",
 			[]map[string]*resolver.NameserverResponse{
 				bothAnswer, bTXTFails, bothAnswer,
 			},
 			alertCounts{},
 		},
 		{
 			"type failing on the first check alerts nothing on the next",
 			[]map[string]*resolver.NameserverResponse{bTXTFails, bothAnswer},
 			alertCounts{},
 		},
 		{
 			"type failing at a nameserver new on that check alerts nothing",
 			[]map[string]*resolver.NameserverResponse{
 				onlyA, bTXTFails, bothAnswer,
 			},
 			alertCounts{},
 		},
 		{
 			"type failing at a recovering nameserver alerts the recovery",
 			[]map[string]*resolver.NameserverResponse{
 				bFails, bTXTFails, bothAnswer,
 			},
 			alertCounts{recoveries: 1},
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			states := savedChecks(tt.checks...)
 			got := countAlerts(t, states[0], states[1:])
 			if got != tt.want {
 				t.Errorf("sent %+v, want %+v", got, tt.want)
 			}
 		})
 	}
 }
 // TestFailedTypeComparedOnceItAnswers saves the checks of each case in
 // turn as TestFailedTypeAlerts does. nsB's TXT query fails on one check,
 // and the TXT record changes: the change is sent as a Record Change for
 // each nameserver on the check where it answers it, and an Inconsistency
 // only when nsB still answers the old record.
 func TestFailedTypeComparedOnceItAnswers(t *testing.T) {
 	t.Parallel()
 	records := map[string][]string{"A": {ip1}, txt: {spf1}}
 	changed := map[string][]string{"A": {ip1}, txt: {spf2}}
 	aOnly := map[string][]string{"A": {ip1}}
 	bothAnswer := map[string]*resolver.NameserverResponse{
 		nsA: response(records), nsB: response(records),
 	}
 	bTXTFails := map[string]*resolver.NameserverResponse{
 		nsA: response(records), nsB: response(aOnly, txt),
 	}
 	bothChange := map[string]*resolver.NameserverResponse{
 		nsA: response(changed), nsB: response(changed),
 	}
 	aChangesBTXTFails := map[string]*resolver.NameserverResponse{
 		nsA: response(changed), nsB: response(aOnly, txt),
 	}
 	bStillOld := map[string]*resolver.NameserverResponse{
 		nsA: response(changed), nsB: response(records),
 	}
 	tests := []struct {
 		name   string
 		checks []map[string]*resolver.NameserverResponse
 		want   alertCounts
 	}{
 		{
 			"change made while the type failed",
 			[]map[string]*resolver.NameserverResponse{
 				bothAnswer, bTXTFails, bothChange,
 			},
 			alertCounts{recordChanges: 2},
 		},
 		{
 			"change seen at one nameserver while the other's type failed",
 			[]map[string]*resolver.NameserverResponse{
 				bothAnswer, aChangesBTXTFails, bothChange,
 			},
 			alertCounts{recordChanges: 2},
 		},
 		{
 			"old record answered after the type failed",
 			[]map[string]*resolver.NameserverResponse{
 				bothAnswer, aChangesBTXTFails, bStillOld,
 			},
 			alertCounts{recordChanges: 1, inconsistencies: 1},
 		},
 		{
 			"change after the type failed on the first check and answered",
 			[]map[string]*resolver.NameserverResponse{
 				bTXTFails, bothAnswer, bothChange,
 			},
 			alertCounts{recordChanges: 2},
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			states := savedChecks(tt.checks...)
 			got := countAlerts(t, states[0], states[1:])
 			if got != tt.want {
 				t.Errorf("sent %+v, want %+v", got, tt.want)
 			}
 		})
 	}
 }
 // TestFailedTypeLeftOutOfMessages checks that a Record Change and an
 // Inconsistency name only the record types they compared. nsB's TXT
 // records are not known on the first check, and on the second either
 // answered or still not known; nsB's A record changes, so both alerts
 // are sent and name the A record alone.
 func TestFailedTypeLeftOutOfMessages(t *testing.T) {
 	t.Parallel()
 	withTXT := map[string][]string{"A": {ip1}, txt: {spf1}}
 	txtNotKnown := func(address string) *state.NameserverRecordState {
 		return &state.NameserverRecordState{
 			Records:      map[string][]string{"A": {address}},
 			FailedTypes:  []string{txt},
 			UnknownTypes: []string{txt},
 			Status:       "ok",
 		}
 	}
 	before := saved(map[string]*state.NameserverRecordState{
 		nsA: answered(withTXT), nsB: txtNotKnown(ip1),
 	})
 	tests := []struct {
 		name  string
 		after *state.HostnameState
 	}{
 		{
 			"TXT answers",
 			saved(map[string]*state.NameserverRecordState{
 				nsA: answered(withTXT),
 				nsB: answered(map[string][]string{"A": {ip2}, txt: {spf1}}),
 			}),
 		},
 		{
 			"TXT still not known",
 			saved(map[string]*state.NameserverRecordState{
 				nsA: answered(withTXT), nsB: txtNotKnown(ip2),
 			}),
 		},
 	}
 	want := map[string]string{
 		"Record Change: " + host: "Hostname: " + host +
 			"\nNameserver: " + nsB + "\nType: A\nOld: " + ip1 + "\nNew: " + ip2,
 		"Inconsistency: " + host: "Hostname: " + host +
 			"\nType: A\n" + nsA + ": " + ip1 + "\n" + nsB + ": " + ip2,
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			// The hostname change detection uses only the notifier.
 			notifier := &mockNotifier{}
 			w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
 			w.DetectHostnameChanges(t.Context(), host, before, tt.after)
 			notifications := notifier.getNotifications()
 			if len(notifications) != len(want) {
 				t.Fatalf(
 					"sent %d notifications, want %d: %v",
 					len(notifications), len(want), notifications,
 				)
 			}
 			for _, n := range notifications {
 				if n.Message != want[n.Title] {
 					t.Errorf(
 						"%s message:\n%s\nwant:\n%s",
 						n.Title, n.Message, want[n.Title],
 					)
 				}
 			}
 		})
 	}
 }
@@ -1,185 +0,0 @@
 package watcher_test
 import (
 	"slices"
 	"testing"
 	"sneak.berlin/go/dnswatcher/internal/state"
 	"sneak.berlin/go/dnswatcher/internal/watcher"
 )
 const (
 	host = "www.example.net"
 	nsA  = "a.ns.example.net."
 	nsB  = "b.ns.example.net."
 	nsC  = "c.ns.example.net."
 	ip1  = "192.0.2.1"
 	ip2  = "192.0.2.2"
 	ip3  = "192.0.2.3"
 )
 // hostnameState builds the state a check with these records leaves behind.
 func hostnameState(
 	records map[string]map[string][]string,
 ) *state.HostnameState {
 	hs := &state.HostnameState{
 		RecordsByNameserver: make(map[string]*state.NameserverRecordState),
 	}
 	for ns, recs := range records {
 		hs.RecordsByNameserver[ns] = &state.NameserverRecordState{
 			Records: recs,
 			Status:  "ok",
 		}
 	}
 	return hs
 }
 func TestNewlyDisagreeingPairs(t *testing.T) {
 	t.Parallel()
 	onlyA := map[string]map[string][]string{nsA: {"A": {ip1}}}
 	agree := map[string]map[string][]string{nsA: {"A": {ip1}}, nsB: {"A": {ip1}}}
 	disagree := map[string]map[string][]string{nsA: {"A": {ip1}}, nsB: {"A": {ip2}}}
 	alert := [][2]string{{nsA, nsB}}
 	// b already disagrees with a and c; then c changes, so a and c,
 	// which agreed, now differ.
 	bDiffers := map[string]map[string][]string{
 		nsA: {"A": {ip1}}, nsB: {"A": {ip2}}, nsC: {"A": {ip1}},
 	}
 	cChanges := map[string]map[string][]string{
 		nsA: {"A": {ip1}}, nsB: {"A": {ip2}}, nsC: {"A": {ip3}},
 	}
 	// Each case starts from the state loaded at startup and runs the
 	// checks in order; want[i] is what check i alerts for.
 	tests := []struct {
 		name   string
 		loaded map[string]map[string][]string
 		checks []map[string]map[string][]string
 		want   [][][2]string
 	}{
 		{
 			name:   "disagreement persisting across checks alerts once",
 			loaded: agree,
 			checks: []map[string]map[string][]string{disagree, disagree, disagree},
 			want:   [][][2]string{alert, nil, nil},
 		},
 		{
 			name:   "disagreement starting on a later check alerts on it",
 			loaded: agree,
 			checks: []map[string]map[string][]string{agree, agree, disagree},
 			want:   [][][2]string{nil, nil, alert},
 		},
 		{
 			name:   "disagreement in the loaded state does not alert",
 			loaded: disagree,
 			checks: []map[string]map[string][]string{disagree, disagree},
 			want:   [][][2]string{nil, nil},
 		},
 		{
 			name:   "nameserver new on the first check and disagreeing alerts once",
 			loaded: onlyA,
 			checks: []map[string]map[string][]string{disagree, disagree},
 			want:   [][][2]string{alert, nil},
 		},
 		{
 			name:   "disagreement after agreeing again alerts again",
 			loaded: agree,
 			checks: []map[string]map[string][]string{disagree, agree, disagree},
 			want:   [][][2]string{alert, nil, alert},
 		},
 		{
 			name:   "new disagreement while another nameserver differs alerts",
 			loaded: bDiffers,
 			checks: []map[string]map[string][]string{cChanges, cChanges},
 			want:   [][][2]string{{{nsA, nsC}}, nil},
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			prev := hostnameState(tt.loaded)
 			for i, records := range tt.checks {
 				current := hostnameState(records)
 				got := watcher.NewlyDisagreeingPairs(prev, current)
 				if !slices.Equal(got, tt.want[i]) {
 					t.Errorf(
 						"check %d: alerted for %v, want %v",
 						i, got, tt.want[i],
 					)
 				}
 				prev = current
 			}
 		})
 	}
 }
 func TestInconsistencyAlert(t *testing.T) {
 	t.Parallel()
 	onlyA := map[string]map[string][]string{nsA: {"A": {ip1}}}
 	agree := map[string]map[string][]string{nsA: {"A": {ip1}}, nsB: {"A": {ip1}}}
 	disagree := map[string]map[string][]string{nsA: {"A": {ip1}}, nsB: {"A": {ip2}}}
 	// Each case starts from the state loaded at startup and then sees
 	// the nameservers disagree on three checks in a row.
 	tests := []struct {
 		name   string
 		loaded map[string]map[string][]string
 		want   int
 	}{
 		{
 			name:   "disagreement lasting several checks alerts once",
 			loaded: agree,
 			want:   1,
 		},
 		{
 			name:   "disagreement in the loaded state does not alert",
 			loaded: disagree,
 			want:   0,
 		},
 		{
 			name:   "nameserver new on the first check and disagreeing alerts once",
 			loaded: onlyA,
 			want:   1,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			// The hostname change detection uses only the notifier.
 			notifier := &mockNotifier{}
 			w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
 			prev := hostnameState(tt.loaded)
 			for range 3 {
 				current := hostnameState(disagree)
 				w.DetectHostnameChanges(t.Context(), host, prev, current)
 				prev = current
 			}
 			got := 0
 			for _, n := range notifier.getNotifications() {
 				if n.Title == "Inconsistency: "+host {
 					got++
 				}
 			}
 			if got != tt.want {
 				t.Errorf("sent %d inconsistency alerts, want %d", got, tt.want)
 			}
 		})
 	}
 }
@@ -5,7 +5,6 @@ import (
 	"context"
 	"sneak.berlin/go/dnswatcher/internal/portcheck"
 	"sneak.berlin/go/dnswatcher/internal/resolver"
 	"sneak.berlin/go/dnswatcher/internal/tlscheck"
 )
@@ -18,11 +17,11 @@ type DNSResolver interface {
 	) ([]string, error)
 	// LookupAllRecords queries all record types for a hostname,
-	// returning each nameserver's response keyed by nameserver.
+	// returning results keyed by nameserver then record type.
 	LookupAllRecords(
 		ctx context.Context,
 		hostname string,
-	) (map[string]*resolver.NameserverResponse, error)
+	) (map[string]map[string][]string, error)
 	// ResolveIPAddresses resolves a hostname to all IP addresses.
 	ResolveIPAddresses(
@@ -1,66 +0,0 @@
 package watcher_test
 import (
 	"testing"
 	"sneak.berlin/go/dnswatcher/internal/watcher"
 )
 // When one nameserver's A record changes and its TXT record does not,
 // the record change and the inconsistency it starts name the A record
 // alone, with its values written as plain text.
 func TestChangeMessagesNameTheChangedType(t *testing.T) {
 	t.Parallel()
 	// A nameserver's records: this A address and the same TXT record.
 	records := func(address string) map[string][]string {
 		return map[string][]string{
 			"A":   {address},
 			"TXT": {"v=spf1 -all"},
 		}
 	}
 	before := hostnameState(map[string]map[string][]string{
 		nsA: records(ip1),
 		nsB: records(ip1),
 	})
 	after := hostnameState(map[string]map[string][]string{
 		nsA: records(ip1),
 		nsB: records(ip2),
 	})
 	// The hostname change detection uses only the notifier.
 	notifier := &mockNotifier{}
 	w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
 	w.DetectHostnameChanges(t.Context(), host, before, after)
 	want := map[string]string{
 		"Record Change: " + host: `Hostname: www.example.net
 Nameserver: b.ns.example.net.
 Type: A
 Old: 192.0.2.1
 New: 192.0.2.2`,
 		"Inconsistency: " + host: `Hostname: www.example.net
 Type: A
 a.ns.example.net.: 192.0.2.1
 b.ns.example.net.: 192.0.2.2`,
 	}
 	notifications := notifier.getNotifications()
 	if len(notifications) != len(want) {
 		t.Fatalf(
 			"sent %d notifications, want %d: %v",
 			len(notifications), len(want), notifications,
 		)
 	}
 	for _, n := range notifications {
 		if n.Message != want[n.Title] {
 			t.Errorf(
 				"%s message:\n%s\nwant:\n%s",
 				n.Title, n.Message, want[n.Title],
 			)
 		}
 	}
 }
@@ -1,151 +0,0 @@
 package watcher_test
 import (
 	"context"
 	"log/slog"
 	"reflect"
 	"testing"
 	"sneak.berlin/go/dnswatcher/internal/livednstest"
 	"sneak.berlin/go/dnswatcher/internal/resolver"
 	"sneak.berlin/go/dnswatcher/internal/watcher"
 )
 const domain = "example.net"
 func TestNSAddressChangeAlerts(t *testing.T) {
 	t.Parallel()
 	// Each case is the nameserver addresses saved by the previous check
 	// and by the current one.
 	tests := []struct {
 		name          string
 		prev, current map[string][]string
 		want          int
 	}{
 		{
 			"same addresses",
 			map[string][]string{nsA: {ip1, ip2}},
 			map[string][]string{nsA: {ip1, ip2}},
 			0,
 		},
 		{
 			"same addresses in another order",
 			map[string][]string{nsA: {ip2, ip1}},
 			map[string][]string{nsA: {ip1, ip2}},
 			0,
 		},
 		{
 			"address replaced",
 			map[string][]string{nsA: {ip1}},
 			map[string][]string{nsA: {ip2}},
 			1,
 		},
 		{
 			"address added",
 			map[string][]string{nsA: {ip1}},
 			map[string][]string{nsA: {ip1, ip2}},
 			1,
 		},
 		{
 			"two nameservers changed",
 			map[string][]string{nsA: {ip1}, nsB: {ip2}},
 			map[string][]string{nsA: {ip3}, nsB: {ip3}},
 			2,
 		},
 		{
 			"nameserver added",
 			map[string][]string{nsA: {ip1}},
 			map[string][]string{nsA: {ip1}, nsB: {ip2}},
 			0,
 		},
 		{
 			"nameserver removed",
 			map[string][]string{nsA: {ip1}, nsB: {ip2}},
 			map[string][]string{nsA: {ip1}},
 			0,
 		},
 		{
 			"state file from before addresses were saved",
 			nil,
 			map[string][]string{nsA: {ip1}, nsB: {ip2}},
 			0,
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			notifier := &mockNotifier{}
 			w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
 			w.DetectNSAddressChanges(t.Context(), domain, tt.prev, tt.current)
 			got := len(notifier.getNotifications())
 			if got != tt.want {
 				t.Errorf("sent %d address changes, want %d", got, tt.want)
 			}
 		})
 	}
 }
 func TestNSAddressChangeAlertNamesDomainNameserverAndAddresses(
 	t *testing.T,
 ) {
 	t.Parallel()
 	notifier := &mockNotifier{}
 	w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
 	w.DetectNSAddressChanges(
 		t.Context(), domain,
 		map[string][]string{nsA: {ip1}},
 		map[string][]string{nsA: {ip2, ip3}},
 	)
 	want := notification{
 		Title: "NS Address Change: " + domain,
 		Message: "Domain: " + domain + "\nNameserver: " + nsA +
 			"\nOld: " + ip1 + "\nNew: " + ip2 + ", " + ip3,
 		Priority: "warning",
 	}
 	got := notifier.getNotifications()
 	if len(got) != 1 || got[0] != want {
 		t.Errorf("sent %v, want %v", got, want)
 	}
 }
 // TestNameserverWithNoAddressKeepsPrevious looks up nameserver names
 // with no address: two under .invalid, whose lookup fails with an
 // error, and one that does not exist under a real zone, which live DNS
 // answers with no address and no error. Each one with addresses saved
 // by the previous check keeps them; the one without gets none.
 func TestNameserverWithNoAddressKeepsPrevious(t *testing.T) {
 	t.Parallel()
 	w := watcher.NewForTest(
 		nil, nil, resolver.NewFromLogger(slog.Default()), nil, nil, nil,
 	)
 	nonexistentNS := "this-surely-does-not-exist-xyz." + testSmallDomain + "."
 	prev := map[string][]string{oldNS1: {oldIP}, nonexistentNS: {oldIP}}
 	var got map[string][]string
 	// The result is the same whether or not live DNS answers, so the
 	// lookup is not retried.
 	_ = livednstest.Run(func(ctx context.Context) error {
 		got = w.ResolveNameserverAddresses(
 			ctx, []string{oldNS1, oldNS2, nonexistentNS}, prev,
 		)
 		return nil
 	})
 	if !reflect.DeepEqual(got, prev) {
 		t.Errorf("saved %v, want %v", got, prev)
 	}
 }
@@ -1,448 +0,0 @@
 package watcher_test
 import (
 	"context"
 	"fmt"
 	"log/slog"
 	"strings"
 	"testing"
 	"time"
 	"sneak.berlin/go/dnswatcher/internal/livednstest"
 	"sneak.berlin/go/dnswatcher/internal/resolver"
 	"sneak.berlin/go/dnswatcher/internal/state"
 	"sneak.berlin/go/dnswatcher/internal/watcher"
 )
 // answered is what a check saves for a nameserver that answered with
 // these records.
 func answered(records map[string][]string) *state.NameserverRecordState {
 	return &state.NameserverRecordState{Records: records, Status: "ok"}
 }
 // failed is what a check saves for a nameserver that did not answer.
 func failed() *state.NameserverRecordState {
 	return &state.NameserverRecordState{
 		Records: map[string][]string{},
 		Status:  "error",
 		Error:   "all queries timed out",
 	}
 }
 // saved builds the hostname state a check saves.
 func saved(
 	byNameserver map[string]*state.NameserverRecordState,
 ) *state.HostnameState {
 	return &state.HostnameState{RecordsByNameserver: byNameserver}
 }
 // alertCounts counts the hostname alerts sent, by kind.
 type alertCounts struct {
 	failures, recoveries, recordChanges, inconsistencies int
 }
 // countAlerts runs the hostname change detection from the state loaded
 // at startup through each check in turn, and counts the alerts sent.
 func countAlerts(
 	t *testing.T,
 	loaded *state.HostnameState,
 	checks []*state.HostnameState,
 ) alertCounts {
 	t.Helper()
 	// The hostname change detection uses only the notifier.
 	notifier := &mockNotifier{}
 	w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
 	prev := loaded
 	for _, current := range checks {
 		w.DetectHostnameChanges(t.Context(), host, prev, current)
 		prev = current
 	}
 	var got alertCounts
 	for _, n := range notifier.getNotifications() {
 		kind, _, _ := strings.Cut(n.Title, ":")
 		switch kind {
 		case "NS Failure":
 			got.failures++
 		case "NS Recovery":
 			got.recoveries++
 		case "Record Change":
 			got.recordChanges++
 		case "Inconsistency":
 			got.inconsistencies++
 		}
 	}
 	return got
 }
 func TestNSFailureAndRecoveryAlerts(t *testing.T) {
 	t.Parallel()
 	records := map[string][]string{"A": {ip1}}
 	bothAnswer := saved(map[string]*state.NameserverRecordState{
 		nsA: answered(records), nsB: answered(records),
 	})
 	bFails := saved(map[string]*state.NameserverRecordState{
 		nsA: answered(records), nsB: failed(),
 	})
 	onlyA := saved(map[string]*state.NameserverRecordState{
 		nsA: answered(records),
 	})
 	bAnswersNoRecords := saved(map[string]*state.NameserverRecordState{
 		nsA: answered(records), nsB: answered(map[string][]string{}),
 	})
 	bAnswersDifferently := saved(map[string]*state.NameserverRecordState{
 		nsA: answered(records), nsB: answered(map[string][]string{"A": {ip2}}),
 	})
 	// Each case starts from the state loaded at startup and runs the
 	// checks in order.
 	tests := []struct {
 		name   string
 		loaded *state.HostnameState
 		checks []*state.HostnameState
 		want   alertCounts
 	}{
 		{
 			"failure lasting several checks alerts once",
 			bothAnswer, []*state.HostnameState{bFails, bFails, bFails},
 			alertCounts{failures: 1},
 		},
 		{
 			"recovery alerts once",
 			bFails, []*state.HostnameState{bothAnswer, bothAnswer},
 			alertCounts{recoveries: 1},
 		},
 		{
 			"failing again after recovering alerts again",
 			bothAnswer, []*state.HostnameState{bFails, bothAnswer, bFails},
 			alertCounts{failures: 2, recoveries: 1},
 		},
 		{
 			"nameserver failing when first seen does not alert",
 			onlyA, []*state.HostnameState{bFails, bFails},
 			alertCounts{},
 		},
 		{
 			"answer with no records is a record change, not a failure",
 			bothAnswer, []*state.HostnameState{bAnswersNoRecords},
 			alertCounts{recordChanges: 1, inconsistencies: 1},
 		},
 		{
 			"recovered nameserver that answers differently disagrees",
 			bFails, []*state.HostnameState{bAnswersDifferently},
 			alertCounts{recoveries: 1, inconsistencies: 1},
 		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			got := countAlerts(t, tt.loaded, tt.checks)
 			if got != tt.want {
 				t.Errorf("sent %+v, want %+v", got, tt.want)
 			}
 		})
 	}
 }
 func TestNSFailureAlertNamesHostnameNameserverAndReason(t *testing.T) {
 	t.Parallel()
 	records := map[string][]string{"A": {ip1}}
 	notifier := &mockNotifier{}
 	w := watcher.NewForTest(nil, nil, nil, nil, nil, notifier)
 	w.DetectHostnameChanges(
 		t.Context(), host,
 		saved(map[string]*state.NameserverRecordState{nsA: answered(records)}),
 		saved(map[string]*state.NameserverRecordState{nsA: failed()}),
 	)
 	notifications := notifier.getNotifications()
 	if len(notifications) != 1 {
 		t.Fatalf("sent %v, want one NS Failure", notifications)
 	}
 	msg := notifications[0].Message
 	if !strings.Contains(msg, host) || !strings.Contains(msg, nsA) ||
 		!strings.Contains(msg, failed().Error) {
 		t.Errorf(
 			"message %q does not name %s, %s and the reason",
 			msg, host, nsA,
 		)
 	}
 }
 // TestNameserverThatNeverAnswers asks a nameserver address where
 // nothing answers, 192.0.2.1, and checks what the watcher saves for it.
 // The deadline outlasts the resolver's first two-second try, as in the
 // resolver's timeout test.
 func TestNameserverThatNeverAnswers(t *testing.T) {
 	t.Parallel()
 	ctx, cancel := context.WithTimeout(t.Context(), 3*time.Second)
 	t.Cleanup(cancel)
 	res := resolver.NewFromLogger(slog.Default())
 	resp, err := res.QueryNameserverIP(ctx, nsA, "192.0.2.1", host)
 	if err != nil {
 		t.Fatal(err)
 	}
 	hs := watcher.BuildHostnameState(
 		map[string]*resolver.NameserverResponse{nsA: resp}, nil, time.Now(),
 	)
 	got := hs.RecordsByNameserver[nsA]
 	if got.Status != "error" || got.Error == "" {
 		t.Errorf(
 			"saved status %q, error %q; want status error with a reason",
 			got.Status, got.Error,
 		)
 	}
 }
 // TestNameserverThatAnswersNXDOMAIN asks a real nameserver about a name
 // that does not exist and checks what the watcher saves for it: NXDOMAIN
 // is an answer, so the nameserver is saved as ok with no error.
 func TestNameserverThatAnswersNXDOMAIN(t *testing.T) {
 	t.Parallel()
 	res := resolver.NewFromLogger(slog.Default())
 	name := "this-surely-does-not-exist-xyz." + testDomain
 	var (
 		ns   string
 		resp *resolver.NameserverResponse
 	)
 	livednstest.Retry(t, "QueryNameserver("+name+")", func(ctx context.Context) error {
 		nameservers, err := res.LookupNS(ctx, testDomain)
 		if err != nil {
 			return err
 		}
 		ns = nameservers[0]
 		resp, err = res.QueryNameserver(ctx, ns, name)
 		if err != nil {
 			return err
 		}
 		// A timeout or a failure is no answer to check.
 		if resp.Status == resolver.StatusTimeout ||
 			resp.Status == resolver.StatusError {
 			return fmt.Errorf(
 				"%w: %s: %s", livednstest.ErrNoAnswer, ns, resp.Error,
 			)
 		}
 		return nil
 	})
 	if resp.Status != resolver.StatusNXDomain {
 		t.Fatalf("%s answered %q for %s, want NXDOMAIN", ns, resp.Status, name)
 	}
 	hs := watcher.BuildHostnameState(
 		map[string]*resolver.NameserverResponse{ns: resp}, nil, time.Now(),
 	)
 	got := hs.RecordsByNameserver[ns]
 	if got.Status != "ok" || got.Error != "" {
 		t.Errorf(
 			"saved status %q, error %q; want status ok with no error",
 			got.Status, got.Error,
 		)
 	}
 }
 // TestNameserverThatRefuses asks a google.com nameserver about
 // cloudflare.com, a zone it does not serve, which it refuses, and checks
 // what the watcher saves for it: REFUSED is no answer, so the nameserver
 // is saved as error with the reason.
 func TestNameserverThatRefuses(t *testing.T) {
 	t.Parallel()
 	const reason = "server returned REFUSED"
 	res := resolver.NewFromLogger(slog.Default())
 	var (
 		ns   string
 		resp *resolver.NameserverResponse
 	)
 	livednstest.Retry(
 		t,
 		"QueryNameserver(cloudflare.com)",
 		func(ctx context.Context) error {
 			nameservers, err := res.LookupNS(ctx, testDomain)
 			if err != nil {
 				return err
 			}
 			ns = nameservers[0]
 			resp, err = res.QueryNameserver(ctx, ns, "cloudflare.com")
 			if err != nil {
 				return err
 			}
 			// A timeout or a network error is no reply at all.
 			if resp.Status == resolver.StatusTimeout ||
 				strings.HasPrefix(resp.Error, "network error") {
 				return fmt.Errorf(
 					"%w: %s: %s", livednstest.ErrNoAnswer, ns, resp.Error,
 				)
 			}
 			return nil
 		},
 	)
 	if resp.Error != reason {
 		t.Fatalf(
 			"%s answered %q (%s) for cloudflare.com, want REFUSED",
 			ns, resp.Status, resp.Error,
 		)
 	}
 	hs := watcher.BuildHostnameState(
 		map[string]*resolver.NameserverResponse{ns: resp}, nil, time.Now(),
 	)
 	got := hs.RecordsByNameserver[ns]
 	if got.Status != failed().Status || got.Error != reason {
 		t.Errorf(
 			"saved status %q, error %q; want status %q, error %q",
 			got.Status, got.Error, failed().Status, reason,
 		)
 	}
 }
 // TestPortStateWhenNoNameserverAnswered runs the port checks on
 // hostname state built here, which gives the name no address. The port
 // state saved for its old address is kept only when the name is a
 // configured hostname or domain and none of its nameservers answered.
 func TestPortStateWhenNoNameserverAnswered(t *testing.T) {
 	t.Parallel()
 	noneAnswered := saved(map[string]*state.NameserverRecordState{
 		nsA: failed(), nsB: failed(),
 	})
 	oneAnsweredNoAddress := saved(map[string]*state.NameserverRecordState{
 		nsA: answered(map[string][]string{}), nsB: failed(),
 	})
 	configured := []string{host}
 	tests := []struct {
 		name      string
 		hostname  *state.HostnameState
 		hostnames []string
 		domains   []string
 		wantKept  bool
 	}{
 		{"no nameserver answered", noneAnswered, configured, nil, true},
 		{
 			"no nameserver answered, configured as a domain",
 			noneAnswered, nil, configured, true,
 		},
 		{
 			"one answered with no address",
 			oneAnsweredNoAddress, configured, nil, false,
 		},
 		{"no nameserver answered, not configured", noneAnswered, nil, nil, false},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 			cfg := defaultTestConfig(t)
 			cfg.Hostnames = tt.hostnames
 			cfg.Domains = tt.domains
 			// The port checks read the saved hostname state and look
 			// nothing up, so the watcher has no resolver.
 			deps := newTestDeps(t, cfg)
 			w := watcher.NewForTest(
 				cfg, deps.state, nil,
 				deps.portChecker, deps.tlsChecker, deps.notifier,
 			)
 			key := ip1 + ":443"
 			deps.state.SetHostnameState(host, tt.hostname)
 			deps.state.SetPortState(key, &state.PortState{
 				Open: true, Hostnames: []string{host},
 			})
 			w.CheckAllPorts(t.Context())
 			_, kept := deps.state.GetPortState(key)
 			if kept != tt.wantKept {
 				t.Errorf("port state %s kept: %v, want %v", key, kept, tt.wantKept)
 			}
 		})
 	}
 }
 // TestPortStateWhenNoNameserverAnsweredAndOtherNameMovesAway saves the
 // port state of an address two configured hostnames resolve to. While
 // none of the first one's nameservers answer, the port checks run with
 // the other one still at that address, then after it moved away; the
 // port state is kept both times.
 func TestPortStateWhenNoNameserverAnsweredAndOtherNameMovesAway(
 	t *testing.T,
 ) {
 	t.Parallel()
 	const other = "mail.example.net"
 	cfg := defaultTestConfig(t)
 	cfg.Hostnames = []string{host, other}
 	// The port checks read the saved hostname state and look nothing
 	// up, so the watcher has no resolver.
 	deps := newTestDeps(t, cfg)
 	w := watcher.NewForTest(
 		cfg, deps.state, nil,
 		deps.portChecker, deps.tlsChecker, deps.notifier,
 	)
 	key := ip1 + ":443"
 	deps.state.SetPortState(key, &state.PortState{
 		Open: true, Hostnames: []string{host, other},
 	})
 	deps.state.SetHostnameState(host, saved(
 		map[string]*state.NameserverRecordState{nsA: failed(), nsB: failed()},
 	))
 	for _, otherIP := range []string{ip1, ip2} {
 		deps.state.SetHostnameState(other, saved(
 			map[string]*state.NameserverRecordState{
 				nsA: answered(map[string][]string{"A": {otherIP}}),
 			},
 		))
 		w.CheckAllPorts(t.Context())
 		if _, kept := deps.state.GetPortState(key); !kept {
 			t.Fatalf("port state %s removed with %s at %s", key, other, otherIP)
 		}
 	}
 }
@@ -4,17 +4,15 @@ import (
 	"context"
 	"fmt"
 	"log/slog"
 	"maps"
 	"slices"
 	"sort"
 	"strings"
 	"sync"
 	"time"
 	"go.uber.org/fx"
 	"sneak.berlin/go/dnswatcher/internal/config"
 	"sneak.berlin/go/dnswatcher/internal/logger"
 	"sneak.berlin/go/dnswatcher/internal/resolver"
 	"sneak.berlin/go/dnswatcher/internal/state"
 	"sneak.berlin/go/dnswatcher/internal/tlscheck"
 )
@@ -49,16 +47,17 @@ type Params struct {
 // Watcher orchestrates all monitoring checks on a schedule.
 type Watcher struct {
-	log       *slog.Logger
+	log              *slog.Logger
-	config    *config.Config
+	config           *config.Config
-	state     *state.State
+	state            *state.State
-	resolver  DNSResolver
+	resolver         DNSResolver
-	portCheck PortChecker
+	portCheck        PortChecker
-	tlsCheck  TLSChecker
+	tlsCheck         TLSChecker
-	notify    Notifier
+	notify           Notifier
-	cancel    context.CancelFunc
+	cancel           context.CancelFunc
-	done      chan struct{} // closed when Run returns
+	firstRun         bool
-	firstRun  bool
+	expiryNotifiedMu sync.Mutex
 	expiryNotified   map[string]time.Time
 }
 // New creates a new Watcher instance wired into the fx lifecycle.
@@ -67,67 +66,72 @@ func New(
 	params Params,
 ) (*Watcher, error) {
 	w := &Watcher{
-		log:       params.Logger.Get(),
+		log:            params.Logger.Get(),
-		config:    params.Config,
+		config:         params.Config,
-		state:     params.State,
+		state:          params.State,
-		resolver:  params.Resolver,
+		resolver:       params.Resolver,
-		portCheck: params.PortCheck,
+		portCheck:      params.PortCheck,
-		tlsCheck:  params.TLSCheck,
+		tlsCheck:       params.TLSCheck,
-		notify:    params.Notify,
+		notify:         params.Notify,
-		firstRun:  true,
+		firstRun:       true,
 		expiryNotified: make(map[string]time.Time),
 	}
 	lifecycle.Append(fx.Hook{
-		OnStart: func(startCtx context.Context) error {
+		OnStart: func(_ context.Context) error {
-			// The fx startup context expires after startup
+			// Use context.Background() — the fx startup context
-			// completes, so the watcher's context drops its
+			// expires after startup completes, so deriving from it
-			// cancellation. The watcher's lifetime is controlled
+			// would cancel the watcher immediately. The watcher's
-			// by w.cancel in OnStop.
+			// lifetime is controlled by w.cancel in OnStop.
-			ctx, cancel := context.WithCancel(
+			ctx, cancel := context.WithCancel(context.Background())
 				context.WithoutCancel(startCtx),
 			)
 			w.cancel = cancel
 			w.done = make(chan struct{})
-			go func() {
+			go w.Run(ctx) //nolint:contextcheck // intentionally not derived from startCtx
 				defer close(w.done)
 				w.Run(ctx)
 			}()
 			return nil
 		},
-		OnStop: func(ctx context.Context) error {
+		OnStop: func(_ context.Context) error {
-			w.cancel()
+			if w.cancel != nil {
-
+				w.cancel()
 			// Run saves state as it returns. Waiting for it here
 			// means the save is done before shutdown goes on.
 			select {
 			case <-w.done:
 				return nil
 			case <-ctx.Done():
 				return fmt.Errorf(
 					"waiting for the watcher to stop: %w",
 					ctx.Err(),
 				)
 			}
 			return nil
 		},
 	})
 	return w, nil
 }
-// Run starts the monitoring loop with periodic scheduling. When ctx
+// NewForTest creates a Watcher without fx for unit testing.
-// is cancelled, it saves state and returns.
+func NewForTest(
 	cfg *config.Config,
 	st *state.State,
 	res DNSResolver,
 	pc PortChecker,
 	tc TLSChecker,
 	n Notifier,
 ) *Watcher {
 	return &Watcher{
 		log:            slog.Default(),
 		config:         cfg,
 		state:          st,
 		resolver:       res,
 		portCheck:      pc,
 		tlsCheck:       tc,
 		notify:         n,
 		firstRun:       true,
 		expiryNotified: make(map[string]time.Time),
 	}
 }
 // Run starts the monitoring loop with periodic scheduling.
 func (w *Watcher) Run(ctx context.Context) {
 	w.log.Info(
 		"watcher starting",
 		"domains", len(w.config.Domains),
 		"hostnames", len(w.config.Hostnames),
-		// As text: the JSON log writes a time.Duration as bare
+		"dnsInterval", w.config.DNSInterval,
-		// nanoseconds.
+		"tlsInterval", w.config.TLSInterval,
 		"dnsInterval", w.config.DNSInterval.String(),
 		"tlsInterval", w.config.TLSInterval.String(),
 	)
 	w.RunOnce(ctx)
@@ -142,7 +146,6 @@ func (w *Watcher) Run(ctx context.Context) {
 	for {
 		select {
 		case <-ctx.Done():
 			w.saveState()
 			w.log.Info("watcher stopped")
 			return
@@ -234,30 +237,36 @@ func (w *Watcher) checkDomain(
 	now := time.Now().UTC()
 	prev, hasPrev := w.state.GetDomainState(domain)
 	var prevAddresses map[string][]string
 	if hasPrev {
 		prevAddresses = prev.NameserverAddresses
 	}
 	addresses := w.resolveNameserverAddresses(
 		ctx, nameservers, prevAddresses,
 	)
 	if hasPrev && !w.firstRun {
 		w.detectNSChanges(ctx, domain, prev.Nameservers, nameservers)
 		w.detectNSAddressChanges(ctx, domain, prevAddresses, addresses)
 	}
 	w.state.SetDomainState(domain, &state.DomainState{
-		Nameservers:         nameservers,
+		Nameservers: nameservers,
-		NameserverAddresses: addresses,
+		LastChecked: now,
 		LastChecked:         now,
 	})
-	// The apex domain's records are also checked as a hostname's, so
+	// Also look up A/AAAA records for the apex domain so that
-	// that the port and TLS checks find its addresses.
+	// port and TLS checks (which read HostnameState) can find
-	w.checkHostname(ctx, domain)
+	// the domain's IP addresses.
 	records, err := w.resolver.LookupAllRecords(ctx, domain)
 	if err != nil {
 		w.log.Error(
 			"failed to lookup records for domain",
 			"domain", domain,
 			"error", err,
 		)
 		return
 	}
 	prevHS, hasPrevHS := w.state.GetHostnameState(domain)
 	if hasPrevHS && !w.firstRun {
 		w.detectHostnameChanges(ctx, domain, prevHS, records)
 	}
 	newState := buildHostnameState(records, now)
 	w.state.SetHostnameState(domain, newState)
 }
 func (w *Watcher) detectNSChanges(
@@ -301,77 +310,11 @@ func (w *Watcher) detectNSChanges(
 	)
 }
 // resolveNameserverAddresses returns the sorted addresses each
 // nameserver's name resolves to. A nameserver whose lookup fails, as it
 // does when no nameserver of the name's zone answers, or finds no
 // address keeps its addresses from prev and is not an address change.
 func (w *Watcher) resolveNameserverAddresses(
 	ctx context.Context,
 	nameservers []string,
 	prev map[string][]string,
 ) map[string][]string {
 	addresses := make(map[string][]string, len(nameservers))
 	for _, ns := range nameservers {
 		ips, err := w.resolver.ResolveIPAddresses(ctx, ns)
 		if err == nil && len(ips) > 0 {
 			sort.Strings(ips)
 			addresses[ns] = ips
 			continue
 		}
 		w.log.Error(
 			"no addresses found for nameserver",
 			"nameserver", ns,
 			"error", err,
 		)
 		if prevIPs, ok := prev[ns]; ok {
 			addresses[ns] = prevIPs
 		}
 	}
 	return addresses
 }
 // detectNSAddressChanges notifies when a nameserver in both checks
 // resolves to different addresses. A nameserver added or removed is
 // reported by detectNSChanges alone, and one with no addresses saved by
 // the previous check, as in a state file from before they were saved,
 // is not compared.
 func (w *Watcher) detectNSAddressChanges(
 	ctx context.Context,
 	domain string,
 	prev, current map[string][]string,
 ) {
 	for ns, cur := range current {
 		old, ok := prev[ns]
 		if !ok || sliceEqual(old, cur) {
 			continue
 		}
 		msg := fmt.Sprintf(
 			"Domain: %s\nNameserver: %s\nOld: %s\nNew: %s",
 			domain, ns,
 			strings.Join(old, ", "),
 			strings.Join(cur, ", "),
 		)
 		w.notify.SendNotification(
 			ctx,
 			"NS Address Change: "+domain,
 			msg,
 			"warning",
 		)
 	}
 }
 func (w *Watcher) checkHostname(
 	ctx context.Context,
 	hostname string,
 ) {
-	results, err := w.resolver.LookupAllRecords(ctx, hostname)
+	records, err := w.resolver.LookupAllRecords(ctx, hostname)
 	if err != nil {
 		w.log.Error(
 			"failed to lookup records",
@@ -382,114 +325,19 @@ func (w *Watcher) checkHostname(
 		return
 	}
-	prev, _ := w.state.GetHostnameState(hostname)
+	now := time.Now().UTC()
 	w.updateHostnameState(
 		ctx, hostname, buildHostnameState(results, prev, time.Now().UTC()),
 	)
 }
 // updateHostnameState finishes a check of hostname from newState, built
 // from its nameservers' answers: it follows the CNAME in them, notifies
 // what changed since the previous check, and saves newState.
 func (w *Watcher) updateHostnameState(
 	ctx context.Context,
 	hostname string,
 	newState *state.HostnameState,
 ) {
 	prev, hasPrev := w.state.GetHostnameState(hostname)
 	w.resolveCNAMEAddresses(ctx, hostname, newState, prev)
 	if hasPrev && !w.firstRun {
-		w.detectHostnameChanges(ctx, hostname, prev, newState)
+		w.detectHostnameChanges(ctx, hostname, prev, records)
 	}
 	newState := buildHostnameState(records, now)
 	w.state.SetHostnameState(hostname, newState)
 }
 // resolveCNAMEAddresses saves in current the addresses at the end of
 // hostname's CNAME chain, when the nameservers' answers in current hold
 // a CNAME and no address, and an empty list otherwise. Every CNAME
 // target the nameservers gave is followed with ResolveIPAddresses and
 // the addresses found for all of them are saved, so nameservers that
 // disagree on the target do not change the result from check to check.
 // The addresses saved in prev, which may be nil, are kept when none of
 // the name's nameservers answered its queries for A, AAAA and CNAME,
 // and when a target cannot be followed, as when no nameserver of a zone
 // in its chain answers.
 func (w *Watcher) resolveCNAMEAddresses(
 	ctx context.Context,
 	hostname string,
 	current, prev *state.HostnameState,
 ) {
 	var prevAddresses []string
 	if prev != nil {
 		prevAddresses = prev.CNAMEAddresses
 	}
 	// Empty, not nil: nil means the addresses are not known.
 	current.CNAMEAddresses = []string{}
 	answered := false
 	targets := make(map[string]bool)
 	for _, nsState := range current.RecordsByNameserver {
 		if nsState.Status != statusOK ||
 			slices.Contains(nsState.FailedTypes, "A") ||
 			slices.Contains(nsState.FailedTypes, "AAAA") ||
 			slices.Contains(nsState.FailedTypes, "CNAME") {
 			continue
 		}
 		answered = true
 		if len(nsState.Records["A"]) > 0 || len(nsState.Records["AAAA"]) > 0 {
 			return
 		}
 		for _, target := range nsState.Records["CNAME"] {
 			targets[target] = true
 		}
 	}
 	if !answered {
 		current.CNAMEAddresses = prevAddresses
 		return
 	}
 	for target := range targets {
 		ips, err := w.resolver.ResolveIPAddresses(ctx, target)
 		if err != nil {
 			w.log.Error(
 				"failed to follow CNAME",
 				"hostname", hostname,
 				"target", target,
 				"error", err,
 			)
 			current.CNAMEAddresses = prevAddresses
 			return
 		}
 		current.CNAMEAddresses = append(current.CNAMEAddresses, ips...)
 	}
 	// Still the empty list when every chain ends in no address.
 	slices.Sort(current.CNAMEAddresses)
 	current.CNAMEAddresses = slices.Compact(current.CNAMEAddresses)
 }
 // buildHostnameState saves each nameserver's response. A nameserver
 // that answered, even with NXDOMAIN or no records, is saved as ok, with
 // the record types whose query failed; one that timed out or failed is
 // saved as error with the reason, and its empty record set is not an
 // answer. prev is the hostname's state from the previous check, or nil.
 func buildHostnameState(
-	results map[string]*resolver.NameserverResponse,
+	records map[string]map[string][]string,
 	prev *state.HostnameState,
 	now time.Time,
 ) *state.HostnameState {
 	hs := &state.HostnameState{
@@ -499,129 +347,49 @@ func buildHostnameState(
 		LastChecked: now,
 	}
-	for ns, resp := range results {
+	for ns, recs := range records {
-		nsState := &state.NameserverRecordState{
+		hs.RecordsByNameserver[ns] = &state.NameserverRecordState{
-			Records:     maps.Clone(resp.Records),
+			Records:     recs,
 			Status:      statusOK,
 			LastChecked: now,
 		}
 		if resp.Status == resolver.StatusTimeout ||
 			resp.Status == resolver.StatusError {
 			nsState.Status = statusError
 			nsState.Error = resp.Error
 		} else {
 			nsState.FailedTypes = resp.FailedTypes
 			var prevNS *state.NameserverRecordState
 			if prev != nil {
 				prevNS = prev.RecordsByNameserver[ns]
 			}
 			keepFailedTypes(nsState, prevNS)
 		}
 		hs.RecordsByNameserver[ns] = nsState
 	}
 	return hs
 }
 // keepFailedTypes copies into nsState, for each record type in its
 // FailedTypes, the records prevNS, the nameserver's state from the
 // previous check, holds for that type, which may be none. When prevNS
 // does not know them either, because the nameserver was new or failing
 // then or the type was in its UnknownTypes, the type goes in
 // nsState.UnknownTypes instead.
 func keepFailedTypes(nsState, prevNS *state.NameserverRecordState) {
 	for _, rtype := range nsState.FailedTypes {
 		if prevNS == nil || prevNS.Status != statusOK ||
 			slices.Contains(prevNS.UnknownTypes, rtype) {
 			nsState.UnknownTypes = append(nsState.UnknownTypes, rtype)
 			continue
 		}
 		if records, ok := prevNS.Records[rtype]; ok {
 			nsState.Records[rtype] = records
 		}
 	}
 }
 func (w *Watcher) detectHostnameChanges(
 	ctx context.Context,
 	hostname string,
-	prev, current *state.HostnameState,
+	prev *state.HostnameState,
 	current map[string]map[string][]string,
 ) {
 	w.detectRecordChanges(ctx, hostname, prev, current)
 	w.detectNSDisappearances(ctx, hostname, prev, current)
-	w.detectNSFailures(ctx, hostname, prev, current)
+	w.detectInconsistencies(ctx, hostname, current)
 	w.detectInconsistencies(ctx, hostname, prev, current)
 	w.detectCNAMEAddressChanges(ctx, hostname, prev, current)
 }
 // detectCNAMEAddressChanges notifies when the addresses at the end of
 // hostname's CNAME chain differ from those the previous check saved,
 // including a change from or to none. When the previous addresses are
 // not known (nil), as on the first check after loading a state file
 // written before they were saved, nothing is compared.
 func (w *Watcher) detectCNAMEAddressChanges(
 	ctx context.Context,
 	hostname string,
 	prev, current *state.HostnameState,
 ) {
 	old, cur := prev.CNAMEAddresses, current.CNAMEAddresses
 	if old == nil || sliceEqual(old, cur) {
 		return
 	}
 	msg := fmt.Sprintf(
 		"Hostname: %s\nOld: %s\nNew: %s",
 		hostname,
 		strings.Join(old, ", "),
 		strings.Join(cur, ", "),
 	)
 	w.notify.SendNotification(
 		ctx,
 		"CNAME Address Change: "+hostname,
 		msg,
 		"warning",
 	)
 }
 // detectRecordChanges compares each nameserver's records with those of
 // the previous check. Only answers are compared: a nameserver that
 // failed on either check has no records to compare. The records kept
 // for a record type whose query failed are compared too, but not those
 // of a type in UnknownTypes on either check, which the message leaves
 // out as well.
 func (w *Watcher) detectRecordChanges(
 	ctx context.Context,
 	hostname string,
-	prev, current *state.HostnameState,
+	prev *state.HostnameState,
 	current map[string]map[string][]string,
 ) {
-	for ns, cur := range current.RecordsByNameserver {
+	for ns, recs := range current {
 		prevNS, ok := prev.RecordsByNameserver[ns]
-		if !ok || prevNS.Status != statusOK || cur.Status != statusOK {
+		if !ok {
 			continue
 		}
-		unknown := slices.Concat(prevNS.UnknownTypes, cur.UnknownTypes)
+		if recordsEqual(prevNS.Records, recs) {
 		oldRecords := withoutTypes(prevNS.Records, unknown)
 		newRecords := withoutTypes(cur.Records, unknown)
 		if recordsEqual(oldRecords, newRecords) {
 			continue
 		}
 		msg := fmt.Sprintf(
-			"Hostname: %s\nNameserver: %s\n%s",
+			"Hostname: %s\nNameserver: %s\n"+
 				"Old: %v\nNew: %v",
 			hostname, ns,
-			recordDifferences(
+			prevNS.Records, recs,
 				"Old", oldRecords,
 				"New", newRecords,
 			),
 		)
 		w.notify.SendNotification(
@@ -636,10 +404,11 @@ func (w *Watcher) detectRecordChanges(
 func (w *Watcher) detectNSDisappearances(
 	ctx context.Context,
 	hostname string,
-	prev, current *state.HostnameState,
+	prev *state.HostnameState,
 	current map[string]map[string][]string,
 ) {
 	for ns, prevNS := range prev.RecordsByNameserver {
-		if _, ok := current.RecordsByNameserver[ns]; ok || prevNS.Status != statusOK {
+		if _, ok := current[ns]; ok || prevNS.Status != statusOK {
 			continue
 		}
@@ -655,72 +424,52 @@ func (w *Watcher) detectNSDisappearances(
 			"error",
 		)
 	}
 }
-// detectNSFailures notifies when a nameserver that answered on the
+	for ns := range current {
 // previous check fails, and when one that failed answers again. A
 // nameserver missing from the previous check is not compared.
 func (w *Watcher) detectNSFailures(
 	ctx context.Context,
 	hostname string,
 	prev, current *state.HostnameState,
 ) {
 	for ns, cur := range current.RecordsByNameserver {
 		prevNS, ok := prev.RecordsByNameserver[ns]
-		if !ok {
+		if !ok || prevNS.Status != statusError {
 			continue
 		}
-		switch {
+		msg := fmt.Sprintf(
-		case prevNS.Status == statusOK && cur.Status == statusError:
+			"Hostname: %s\nNameserver: %s recovered",
-			msg := fmt.Sprintf(
+			hostname, ns,
-				"Hostname: %s\nNameserver: %s\nError: %s",
+		)
 				hostname, ns, cur.Error,
 			)
-			w.notify.SendNotification(
+		w.notify.SendNotification(
-				ctx,
+			ctx,
-				"NS Failure: "+hostname,
+			"NS Recovery: "+hostname,
-				msg,
+			msg,
-				"error",
+			"success",
-			)
+		)
 		case prevNS.Status == statusError && cur.Status == statusOK:
 			msg := fmt.Sprintf(
 				"Hostname: %s\nNameserver: %s recovered",
 				hostname, ns,
 			)
 			w.notify.SendNotification(
 				ctx,
 				"NS Recovery: "+hostname,
 				msg,
 				"success",
 			)
 		}
 	}
 }
 func (w *Watcher) detectInconsistencies(
 	ctx context.Context,
 	hostname string,
-	prev, current *state.HostnameState,
+	current map[string]map[string][]string,
 ) {
-	for _, pair := range newlyDisagreeingPairs(prev, current) {
+	nameservers := make([]string, 0, len(current))
-		ns1, ns2 := pair[0], pair[1]
+	for ns := range current {
-		state1 := current.RecordsByNameserver[ns1]
+		nameservers = append(nameservers, ns)
-		state2 := current.RecordsByNameserver[ns2]
+	}
-		// The record types left out of the comparison are left out of
+	sort.Strings(nameservers)
-		// the message too.
+
-		failed := slices.Concat(state1.FailedTypes, state2.FailedTypes)
+	for i := range len(nameservers) - 1 {
 		ns1 := nameservers[i]
 		ns2 := nameservers[i+1]
 		if recordsEqual(current[ns1], current[ns2]) {
 			continue
 		}
 		msg := fmt.Sprintf(
-			"Hostname: %s\n%s",
+			"Hostname: %s\n%s: %v\n%s: %v",
 			hostname,
-			recordDifferences(
+			ns1, current[ns1],
-				ns1, withoutTypes(state1.Records, failed),
+			ns2, current[ns2],
 				ns2, withoutTypes(state2.Records, failed),
 			),
 		)
 		w.notify.SendNotification(
@@ -732,53 +481,6 @@ func (w *Watcher) detectInconsistencies(
 	}
 }
 // newlyDisagreeingPairs returns every pair of nameservers that answered
 // in current and whose records differ there, in sorted order of name,
 // except pairs where both nameservers answered in prev and already
 // differed there. A nameserver missing from prev, or that failed there,
 // is paired with every nameserver it differs from. A nameserver that
 // failed in current has no records to compare and is in no pair. In
 // both checks, a record type whose query failed at either nameserver is
 // not compared.
 func newlyDisagreeingPairs(
 	prev, current *state.HostnameState,
 ) [][2]string {
 	nameservers := make([]string, 0, len(current.RecordsByNameserver))
 	for ns, cur := range current.RecordsByNameserver {
 		if cur.Status == statusOK {
 			nameservers = append(nameservers, ns)
 		}
 	}
 	sort.Strings(nameservers)
 	var pairs [][2]string
 	for i, ns1 := range nameservers {
 		for _, ns2 := range nameservers[i+1:] {
 			if nameserversAgree(
 				current.RecordsByNameserver[ns1],
 				current.RecordsByNameserver[ns2],
 			) {
 				continue
 			}
 			prev1, ok1 := prev.RecordsByNameserver[ns1]
 			prev2, ok2 := prev.RecordsByNameserver[ns2]
 			if ok1 && ok2 &&
 				prev1.Status == statusOK && prev2.Status == statusOK &&
 				!nameserversAgree(prev1, prev2) {
 				continue
 			}
 			pairs = append(pairs, [2]string{ns1, ns2})
 		}
 	}
 	return pairs
 }
 func (w *Watcher) checkAllPorts(ctx context.Context) {
 	// Phase 1: Build current IP:port → hostname associations
 	// from fresh DNS data.
@@ -861,51 +563,17 @@ func parsePortKey(key string) (string, int) {
 }
 // cleanupStalePorts removes port state entries that are no
-// longer referenced by any hostname in the current DNS data. An
+// longer referenced by any hostname in the current DNS data.
 // entry saved for a configured name none of whose nameservers
 // answered is kept: that name's addresses are not known, not gone.
 func (w *Watcher) cleanupStalePorts(
 	currentAssociations map[string][]string,
 ) {
 	for _, key := range w.state.GetAllPortKeys() {
-		if _, exists := currentAssociations[key]; exists {
+		if _, exists := currentAssociations[key]; !exists {
-			continue
+			w.state.DeletePortState(key)
 		}
 		ps, ok := w.state.GetPortState(key)
 		if ok && slices.ContainsFunc(ps.Hostnames, w.noNameserverAnswered) {
 			continue
 		}
 		w.state.DeletePortState(key)
 	}
 }
 // noNameserverAnswered reports whether name is a configured domain or
 // hostname and none of its nameservers answered on its last check.
 func (w *Watcher) noNameserverAnswered(name string) bool {
 	if !slices.Contains(w.config.Hostnames, name) &&
 		!slices.Contains(w.config.Domains, name) {
 		return false
 	}
 	hs, ok := w.state.GetHostnameState(name)
 	if !ok {
 		return false
 	}
 	for _, nsState := range hs.RecordsByNameserver {
 		if nsState.Status == statusOK {
 			return false
 		}
 	}
 	return true
 }
 // collectIPs returns the addresses saved for hostname: those in its
 // nameservers' A and AAAA records, and those at the end of its CNAME
 // chain.
 func (w *Watcher) collectIPs(hostname string) []string {
 	hs, ok := w.state.GetHostnameState(hostname)
 	if !ok {
@@ -924,10 +592,6 @@ func (w *Watcher) collectIPs(hostname string) []string {
 		}
 	}
 	for _, ip := range hs.CNAMEAddresses {
 		ipSet[ip] = true
 	}
 	result := make([]string, 0, len(ipSet))
 	for ip := range ipSet {
 		result = append(result, ip)
@@ -945,13 +609,6 @@ func (w *Watcher) checkSinglePort(
 	hostnames []string,
 ) {
 	result, err := w.portCheck.CheckPort(ctx, ip, port)
 	// A check the context cut short says nothing about the port, so it
 	// is neither saved nor notified.
 	if ctx.Err() != nil {
 		return
 	}
 	if err != nil {
 		w.log.Error(
 			"port check failed",
@@ -986,24 +643,9 @@ func (w *Watcher) checkSinglePort(
 		)
 	}
 	// A configured name on the saved list none of whose nameservers
 	// answered stays on it, so the entry is kept when the other names
 	// stop resolving to this address.
 	savedHostnames := slices.Clone(hostnames)
 	if hasPrev {
 		for _, name := range prev.Hostnames {
 			if !slices.Contains(hostnames, name) && w.noNameserverAnswered(name) {
 				savedHostnames = append(savedHostnames, name)
 			}
 		}
 		sort.Strings(savedHostnames)
 	}
 	w.state.SetPortState(key, &state.PortState{
 		Open:        result.Open,
-		Hostnames:   savedHostnames,
+		Hostnames:   hostnames,
 		LastChecked: now,
 	})
 }
@@ -1042,13 +684,6 @@ func (w *Watcher) checkTLSCert(
 	hostname string,
 ) {
 	cert, err := w.tlsCheck.CheckCertificate(ctx, ip, hostname)
 	// A check the context cut short says nothing about the certificate,
 	// so it is neither saved nor notified.
 	if ctx.Err() != nil {
 		return
 	}
 	certKey := fmt.Sprintf("%s:%d:%s", ip, tlsPort, hostname)
 	now := time.Now().UTC()
 	prev, hasPrev := w.state.GetCertificateState(certKey)
@@ -1187,6 +822,22 @@ func (w *Watcher) checkTLSExpiry(
 		return
 	}
 	// Deduplicate expiry warnings: don't re-notify for the same
 	// hostname within the TLS check interval.
 	dedupKey := fmt.Sprintf("expiry:%s:%s", hostname, ip)
 	w.expiryNotifiedMu.Lock()
 	lastNotified, seen := w.expiryNotified[dedupKey]
 	if seen && time.Since(lastNotified) < w.config.TLSInterval {
 		w.expiryNotifiedMu.Unlock()
 		return
 	}
 	w.expiryNotified[dedupKey] = time.Now()
 	w.expiryNotifiedMu.Unlock()
 	msg := fmt.Sprintf(
 		"Host: %s\nIP: %s\nCN: %s\n"+
 			"Expires: %s (%.0f days)",
@@ -1212,9 +863,8 @@ func (w *Watcher) saveState() {
 // maybeSendTestNotification sends a startup status notification
 // after the first full scan completes, if SEND_TEST_NOTIFICATION
-// is enabled. The message is informational, not an error or anomaly
+// is enabled. The message is clearly informational ("all ok")
-// alert. It is written before it reaches any endpoint, so it claims
+// and not an error or anomaly alert.
 // nothing about whether the endpoints work.
 func (w *Watcher) maybeSendTestNotification(ctx context.Context) {
 	if !w.config.SendTestNotification {
 		return
@@ -1226,8 +876,7 @@ func (w *Watcher) maybeSendTestNotification(ctx context.Context) {
 		"dnswatcher has started and completed its initial scan.\n"+
 			"Monitoring %d domain(s) and %d hostname(s).\n"+
 			"Tracking %d port endpoint(s) and %d TLS certificate(s).\n"+
-			"This is a test notification, sent to every configured "+
+			"All notification channels are working.",
 			"notification endpoint.",
 		len(snap.Domains),
 		len(snap.Hostnames),
 		len(snap.Ports),
@@ -1255,33 +904,6 @@ func toSet(items []string) map[string]bool {
 	return set
 }
 // nameserversAgree reports whether two nameservers' states from the same
 // check hold the same records, leaving out the record types either lists
 // in FailedTypes: the records held for those are kept from an earlier
 // check, or not known.
 func nameserversAgree(a, b *state.NameserverRecordState) bool {
 	failed := slices.Concat(a.FailedTypes, b.FailedTypes)
 	return recordsEqual(
 		withoutTypes(a.Records, failed), withoutTypes(b.Records, failed),
 	)
 }
 // withoutTypes returns a copy of records without the record types in
 // types.
 func withoutTypes(
 	records map[string][]string,
 	types []string,
 ) map[string][]string {
 	records = maps.Clone(records)
 	for _, rtype := range types {
 		delete(records, rtype)
 	}
 	return records
 }
 func recordsEqual(
 	a, b map[string][]string,
 ) bool {
@@ -1299,54 +921,6 @@ func recordsEqual(
 	return true
 }
 // recordDifferences describes, in sorted order of type, each record
 // type whose values differ between a and b: a line naming the type,
 // then a line with a's values after labelA and one with b's after
 // labelB. Types with the same values in both are left out.
 func recordDifferences(
 	labelA string, a map[string][]string,
 	labelB string, b map[string][]string,
 ) string {
 	types := make([]string, 0, len(a)+len(b))
 	for recordType := range a {
 		types = append(types, recordType)
 	}
 	for recordType := range b {
 		if _, ok := a[recordType]; !ok {
 			types = append(types, recordType)
 		}
 	}
 	sort.Strings(types)
 	var lines []string
 	for _, recordType := range types {
 		if sliceEqual(a[recordType], b[recordType]) {
 			continue
 		}
 		lines = append(lines,
 			"Type: "+recordType,
 			labelA+": "+joinValues(a[recordType]),
 			labelB+": "+joinValues(b[recordType]),
 		)
 	}
 	return strings.Join(lines, "\n")
 }
 // joinValues lists record values separated by commas, or says none.
 func joinValues(values []string) string {
 	if len(values) == 0 {
 		return "none"
 	}
 	return strings.Join(values, ", ")
 }
 func sliceEqual(a, b []string) bool {
 	if len(a) != len(b) {
 		return false
@@ -1,9 +0,0 @@
 {
    "name": "dnswatcher-tooling",
    "version": "0.0.0",
    "private": true,
    "description": "Pins the prettier that script/fmt and script/fmt-check run against this repo's markdown. Not a JavaScript project; nothing here is imported, published, or shipped.",
    "devDependencies": {
        "prettier": "3.9.6"
    }
 }
@@ -3,16 +3,18 @@
 # this repo. Idempotent: every install is guarded by a check so already
 # installed tools are skipped. Base tooling comes from nix, apt, brew,
 # or apk (detected in that order); assumes nothing is present.
-# goimports is not installed here: script/fmt and script/fmt-check-go
+# golangci-lint and goimports are installed via `go install` at the same
-# run it with `go run` at a pinned commit.
+# pinned commits the Dockerfile uses (never "latest").
 # The linter is NOT installed here: golangci-lint runs via docker only
 # (script/lint), pinned by image digest, so its only prerequisite is a
 # working docker. Nor is prettier: script/fmt and
 # script/fmt-check-markdown run it in a container from Dockerfile.fmt.
 set -eu
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 # Pinned versions, 2026-08-07 (same pins as the Dockerfile)
 # golangci-lint v2.12.2
 GOLANGCI_LINT_REF="github.com/golangci/golangci-lint/v2/cmd/golangci-lint@c0d3ddc9cf3faa61a4e378e879ece580256d76e5"
 # goimports v0.42.0
 GOIMPORTS_REF="golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0"
 PKGMGR=""
 SUDO=""
 APT_UPDATED=""
@@ -67,13 +69,10 @@ main() {
    if missing make; then pkg_install gnumake make make make; fi
    if missing go; then pkg_install go golang go go; fi
-    # Linting and the markdown formatter run via docker only. Warn,
+    # Lint/format tools, pinned via go install (installs into
-    # don't fail: building and testing work without it.
+    # "$(go env GOPATH)/bin"; ensure that is on your PATH).
-    if missing docker; then
+    if missing golangci-lint; then go install "$GOLANGCI_LINT_REF"; fi
-        echo "bootstrap: WARNING: docker not found; install it to" \
+    if missing goimports; then go install "$GOIMPORTS_REF"; fi
            "run make lint, make fmt, make fmt-check, make check" \
            "and make docker." >&2
    fi
    go mod download
@@ -1,23 +1,18 @@
 #!/bin/sh
-# script/cibuild: run the CI build. The Dockerfile's lint stage runs
+# script/cibuild: run the CI build. The Dockerfile runs make check, and
-# the Go half of make fmt-check and golangci-lint; its builder stage
+# the CHECK_EPOCH build argument below is fresh on every invocation, so
-# runs make test and make build. The markdown half of make fmt-check
+# the check layer is never served from the Docker layer cache: a
-# runs after that build, as its own build of Dockerfile.fmt, because
+# successful build means the checks were executed and passed on this
-# there is no docker inside a docker build.
+# run, not on some earlier one. Only the check step and the steps after
-#
+# it are invalidated; the toolchain install and go mod download stay
-# --no-cache-filter=lint,builder runs both stages on every invocation;
+# cached.
 # otherwise an unchanged tree is served from the layer cache and passes
 # without linting or querying live DNS. script/fmt-check-markdown busts
 # its own cache the same way.
 set -eu
-SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 main() {
    cd "$ROOT"
-    docker build --no-cache-filter=lint,builder .
+    docker build --build-arg CHECK_EPOCH="$(date +%s%N)" .
    "$SCRIPT_DIR/fmt-check-markdown"
 }
 main "$@"
@@ -1,10 +1,6 @@
 #!/bin/sh
 # script/docker: build the Docker image tagged with the project name.
-# The tag comes from script/projectname.
+# Identical in all repos; the tag comes from script/projectname.
 #
 # --no-cache-filter=lint,builder runs the lint stage and the builder
 # stage (make test) on every invocation; otherwise an unchanged tree is
 # served from the layer cache without linting or querying live DNS.
 set -eu
 SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
@@ -12,15 +8,7 @@ ROOT="$(cd "$SCRIPT_DIR/.." && pwd -P)"
 main() {
    cd "$ROOT"
-    # Own line: a failing command substitution inside an argument does
+    docker build -t "$("$SCRIPT_DIR/projectname")" .
    # not trip `set -e`, so the inline form degrades silently to an
    # empty constant. The VERSION build arg takes precedence over what
    # the build would derive from the .git in its context.
    version="$(git describe --tags --always --dirty 2>/dev/null || true)"
    [ -n "$version" ] || version="unknown"
    docker build --no-cache-filter=lint,builder \
        --build-arg VERSION="$version" \
        -t "$("$SCRIPT_DIR/projectname")" .
 }
 main "$@"
@@ -1,65 +1,13 @@
 #!/bin/sh
-# script/fmt: format all files (writes). Go with gofmt and goimports on
+# script/fmt: format all files (writes).
 # the host, markdown with the prettier pinned by Dockerfile.fmt.
 #
 # goimports runs with `go run` at a pinned commit, never from PATH, so
 # every machine formats with the same version and nothing installs it.
 #
 # The markdown pass is a `docker build --output type=local` rather than a
 # `docker run -v`, so it needs no bind mount and behaves the same against
 # a remote daemon; the formatted documents come back out of the build and
 # are copied over the tree here.
 #
 # Unlike script/fmt-check-markdown this does not bust the cache: it is
 # not a gate, and any edit to a document changes the COPY layer above the
 # prettier step, so a cached result is a result over this exact tree.
 set -eu
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 # goimports v0.42.0, 2026-08-07. Must match script/fmt-check-go.
 GOIMPORTS_REF="golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0"
 # Must match the export stage name in Dockerfile.fmt.
 stage=fmt-out
 die() {
    echo "script/fmt: $*" >&2
    exit 1
 }
 main() {
    cd "$ROOT"
    gofmt -s -w .
-    go run "$GOIMPORTS_REF" -w .
+    goimports -w .
    tmp="$(mktemp -d "${TMPDIR:-/tmp}/dnswatcher-fmt.XXXXXX")"
    trap 'rm -rf "$tmp"' EXIT INT TERM
    docker build \
        --target "$stage" \
        --output "type=local,dest=$tmp/out" \
        -f Dockerfile.fmt .
    # An empty export means prettier was handed nothing, which must not
    # read as "already formatted".
    (cd "$tmp/out" && find . -type f -name '*.md') |
        sed 's|^\./||' | LC_ALL=C sort >"$tmp/files"
    [ -s "$tmp/files" ] ||
        die "the formatting build produced no markdown; the build" \
            "context reached prettier empty"
    # Copied only where the bytes differ, so an already-formatted tree
    # keeps its timestamps and says nothing.
    while IFS= read -r f; do
        [ -n "$f" ] || continue
        if [ -f "$f" ] && cmp -s "$tmp/out/$f" "$f"; then
            continue
        fi
        cp "$tmp/out/$f" "$f"
        echo "prettier: reformatted $f"
    done <"$tmp/files"
 }
 main "$@"
@@ -1,14 +1,18 @@
 #!/bin/sh
-# script/fmt-check: check formatting (read-only). Same tools and scope
+# script/fmt-check: check formatting (read-only). Same scope as
-# as script/fmt, but fails instead of writing: the Go on the host, the
+# script/fmt, but fails instead of writing.
 # markdown with prettier in a container.
 set -eu
-SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd -P)"
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 main() {
-    "$SCRIPT_DIR/fmt-check-go"
+    cd "$ROOT"
-    "$SCRIPT_DIR/fmt-check-markdown"
+    files="$(gofmt -l .)"
    if [ -n "$files" ]; then
        echo "gofmt: files not formatted:" >&2
        echo "$files" >&2
        exit 1
    fi
 }
 main "$@"
@@ -1,31 +0,0 @@
 #!/bin/sh
 # script/fmt-check-go: fail unless every Go source is formatted the way
 # script/fmt would leave it, and name the files that are not. Read-only.
 #
 # Its own script because the Dockerfile's lint stage runs this half
 # alone: there is no docker inside a docker build to run the markdown
 # half in.
 set -eu
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 # goimports v0.42.0, 2026-08-07. Must match script/fmt.
 GOIMPORTS_REF="golang.org/x/tools/cmd/goimports@009367f5c17a8d4c45a961a3a509277190a9a6f0"
 main() {
    cd "$ROOT"
    files="$(gofmt -s -l .)"
    if [ -n "$files" ]; then
        echo "gofmt: files not formatted:" >&2
        echo "$files" >&2
        exit 1
    fi
    files="$(go run "$GOIMPORTS_REF" -l .)"
    if [ -n "$files" ]; then
        echo "goimports: files not formatted:" >&2
        echo "$files" >&2
        exit 1
    fi
 }
 main "$@"
@@ -1,29 +0,0 @@
 #!/bin/sh
 # script/fmt-check-markdown: fail unless every .md is formatted the way
 # script/fmt would leave it. Read-only.
 #
 # prettier is never installed on the host: it runs in a container built
 # from Dockerfile.fmt, pinned by package.json and yarn.lock.
 # --no-cache-filter is here for the reason script/lint gives: a cached
 # build checks nothing.
 #
 # Its own script because script/cibuild runs this half alone, after the
 # Dockerfile's lint stage has checked the Go.
 set -eu
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 # Must match the markdown check stage name in Dockerfile.fmt.
 stage=fmt-check
 main() {
    cd "$ROOT"
    docker build \
        --progress=plain \
        --no-cache-filter="$stage" \
        --target "$stage" \
        -f Dockerfile.fmt \
        .
 }
 main "$@"
@@ -7,20 +7,7 @@ ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 main() {
    cd "$ROOT"
-    # Stop if this directory is not the top of its own git checkout, for
+    hook=".git/hooks/pre-commit"
    # example a copy inside another repository, whose hook must not be
    # replaced.
    if [ "$(git rev-parse --show-toplevel)" != "$ROOT" ]; then
        echo "install-precommit: $ROOT is not the top of a git checkout" >&2
        exit 1
    fi
    # Ask git for the repository's own git directory: .git is a file, not
    # a directory, in some checkouts (for example a clone made with
    # --separate-git-dir). core.hooksPath is deliberately not followed, so
    # the hook is never written outside this repository.
    hooks="$(git rev-parse --git-common-dir)/hooks"
    mkdir -p "$hooks"
    hook="$hooks/pre-commit"
    printf '#!/bin/sh\nset -e\nscript/precommit\n' > "$hook"
    chmod +x "$hook"
    echo "pre-commit hook installed: runs script/precommit"
@@ -1,28 +1,12 @@
 #!/bin/sh
-# script/lint: run the linter. golangci-lint is never installed or run
+# script/lint: run the linter.
 # on the host: it runs via docker only, one way, everywhere. This
 # builds Dockerfile.lint, which COPYs the repo into the digest-pinned
 # golangci-lint image and lints as a build step, so a successful build
 # means a clean lint.
 #
 # --no-cache-filter=lint forces the lint stage (source copy + linter
 # run) to execute on every invocation. Without it an unchanged tree
 # returns success in well under a second having linted nothing. The
 # deps stage (base image + go mod download) stays cached, and no global
 # cache invalidation is performed. --progress=plain keeps the linter's
 # own output visible.
 set -eu
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 main() {
    cd "$ROOT"
-    docker build \
+    golangci-lint run --config .golangci.yml ./...
        --progress=plain \
        --no-cache-filter=lint \
        --target lint \
        -f Dockerfile.lint \
        .
 }
 main "$@"
@@ -1,35 +1,12 @@
 #!/bin/sh
 # script/test: run the test suite.
 #
 # -count=1 disables Go's test cache, and is load-bearing here. This
 # suite queries live DNS on every run by policy (TESTING.md); a cached
 # result is a replay of an earlier run's output with no query made at
 # all. On an unchanged tree the whole suite would return success in
 # under a second having resolved nothing, which makes the repeated-run
 # green that is used as evidence for flakiness fixes worthless. Do not
 # remove it.
 #
 # Conditional verbose rerun per REPO_POLICIES.md: run quiet first so
 # CI and docker build logs stay readable, and rerun with -v only on
 # failure. The rerun also carries -count=1 (a cached replay of the
 # failure would show nothing new), and the exit status is forced to 1
 # no matter how the rerun ends: the first failure already proved the
 # suite broken, so a flaky test that passes the second time must not
 # turn the build green.
 #
 # -timeout 90s is a deliberate backstop above the 60s hard cap on
 # suite duration. Do not lower it.
 set -eu
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 main() {
    cd "$ROOT"
-    go test -count=1 -race -timeout 90s -cover ./... || {
+    go test -v -race -timeout 30s -cover ./...
        echo "--- Rerunning with -v for details ---" >&2
        go test -count=1 -race -timeout 90s -v ./... || true
        exit 1
    }
 }
 main "$@"
@@ -1,8 +0,0 @@
 # THIS IS AN AUTOGENERATED FILE. DO NOT EDIT THIS FILE DIRECTLY.
 # yarn lockfile v1
 prettier@3.9.6:
  version "3.9.6"
  resolved "https://registry.yarnpkg.com/prettier/-/prettier-3.9.6.tgz#b3ea5146515d40fc53f18aa63f74dfab1e10dbf6"
  integrity sha512-OpN0zzVdiaiAhxpuuj5efpIS4sY9j7bY6uR5mnj5yPzGkdkjNKSJeUThPb60Jw29QuAZgA4o+/iB49kFiaBX6g==