Go tests run with -race and -cover under Go's own timeout (closes #88)

backend/script/test runs go test -timeout 30s -race -cover and, if
that fails, runs it again with -v and fails. The root script/test drops
its one 30-second timeout around both halves: from a cold Go build
cache, compiling the tests with -race used it all up on four cores.
Each half keeps its own limit. The builder stage of the Dockerfile
gains gcc and musl-dev for the race detector; make build still sets
CGO_ENABLED=0. New tests: the health check's answer, a valid report's
answer, a report file's exact lines, and the flush at the 10 MiB
threshold. The handlers TestImport stub is gone.

Model: opus-5-5

Dockerfile

@@ -68,9 +68,8 @@ RUN yarn install --frozen-lockfile
 RUN apk add --no-cache git make
 COPY . .
 # make frontend-check is the frontend half of make check (test + lint +
-# fmt-check); its test step runs the unit tests, then the production
+# fmt-check); its test step is the production yarn build, so this both
-# yarn build, so this both produces dist/ and gates the image on
+# produces dist/ and gates the image on lint/fmt-check/test regressions.
-# lint/fmt-check/test regressions.
 # This node stage has neither Go nor Docker; the lint and builder stages
 # above gate the backend half.
 RUN make frontend-check

README.md

@@ -39,11 +39,9 @@ halves, so the root `make check` fails if either one is broken. We provide:
 - `script/bootstrap` — install all dependencies (the pinned node via nvm unless
   one new enough for the frontend's dependencies is installed, yarn via
   corepack, `yarn install --frozen-lockfile`, the pinned Go unless one at least
-  as new as `backend/go.mod` asks for is installed, the Go modules, and gcc with
+  as new as `backend/go.mod` asks for is installed, and the Go modules), linking
-  the C library headers unless gcc is installed, for the race detector in
+  what it installs itself into `~/.local/bin`, which has to be on `PATH`. It
-  `make test`), linking what it installs itself into `~/.local/bin`, which has
+  installs no Go linter and not Docker: `make lint` runs the linter in Docker
-  to be on `PATH`. It installs no Go linter and not Docker: `make lint` runs the
-  linter in Docker
 - `script/setup` — make a fresh clone ready for development: bootstrap plus the
   git pre-commit hook
 - `script/projectname` — print the project name (used for the Docker image tag)
@@ -54,8 +52,8 @@ halves, so the root `make check` fails if either one is broken. We provide:
 - `script/fmt` — format all files (writes): prettier, then gofmt over `backend/`
 - `script/fmt-check` — check formatting (read-only): prettier, then gofmt
 - `script/check` — run test, lint, and fmt-check
-- `script/frontend-test` — run the unit tests in `test/unit/` with Node's
+- `script/frontend-test` — run the production build as the frontend's test (no
-  built-in test runner, then the production build
+  unit tests yet)
 - `script/frontend-lint` — run prettier in check mode
 - `script/frontend-fmt` — format everything prettier understands (writes)
 - `script/frontend-fmt-check` — check prettier formatting (read-only)
@@ -138,14 +136,8 @@ Local hosts are tracked separately from WAN stats.
 ### Latency measurement
 
 HEAD requests with `mode: 'no-cors'` and `cache: 'no-store'`, timed with
-`performance.now()`. Each check times out after 80% of the refresh interval (24
+`performance.now()`. 1-second timeout; anything over 1000ms is clamped to
-seconds at 30 seconds) and is then recorded as a timeout, so a round's checks
+unreachable. IPv4 only.
-have all finished before the next round is due. When no WAN host answers, a
-recovery probe checks 4 random WAN hosts every half second, giving up the checks
-it started half a second before. As soon as one answers, a new round starts at
-once, as it does after an interval change. A round started early gives up the
-last round's checks if they are still waiting, and that round records nothing,
-so rounds never overlap. IPv4 only.
 
 ### Color coding
 

TODO.md

@@ -28,20 +28,11 @@ latest run passes.
   that fails, runs it again with `-v` and fails. Go's `-timeout` bounds the
   tests, not their compile; the root `script/test` no longer puts one 30-second
   timeout around both halves, which a cold Go build cache could use up on
-  compiling alone. The race detector needs a C compiler: the builder stage of
+  compiling alone. The builder stage of `Dockerfile` has gcc and musl-dev for
-  `Dockerfile` has gcc and musl-dev, and `script/bootstrap` installs gcc, with
+  the race detector; the binary is still built with `CGO_ENABLED=0`. New tests
-  the C library headers on apt and apk, when gcc is missing; the binary is still
+  cover the health check's answer, a valid report's answer, a report file's
-  built with `CGO_ENABLED=0`. New tests cover the health check's answer, a valid
+  exact contents, and the flush when the buffer reaches 10 MiB; the handlers'
-  report's answer, a report file's exact contents, and the flush when the buffer
+  `TestImport` stub is gone
-  reaches 10 MiB; the handlers' `TestImport` stub is gone
-- 2026-10-03: each target check times out after 80% of the refresh interval
-  (issue #78), 24 seconds at 30 seconds, where it was capped at 3 seconds. A
-  round started early, after an interval change or when the recovery probe finds
-  a target answering, gives up the last round's checks if they are still
-  waiting, so rounds never overlap; the recovery probe gives up its own checks
-  after half a second. The frontend has its first unit tests, run by
-  `script/frontend-test` with Node's built-in test runner; for them,
-  `index.html` now links `src/styles.css`, which `src/main.js` used to import
 - 2026-09-29: the container sets up its own data directory (issue #75):
   `bin/entrypoint.sh`, still as root, creates `DATA_DIR` if missing and gives it
   and `/data` to the `netwatch` user with mode 750 before starting the backend

index.html

@@ -9,9 +9,6 @@
             type="image/svg+xml"
             href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>📡</text></svg>"
         />
-        <!-- Linked here, not imported by src/main.js, so the unit tests can
-             import that module in Node, which cannot import CSS. -->
-        <link rel="stylesheet" href="/src/styles.css" />
     </head>
     <body class="bg-gray-900 text-white min-h-screen">
         <div id="app"></div>

script/bootstrap

@@ -64,8 +64,7 @@ detect_pkgmgr() {
     fi
 }
 
-# pkg_install <nix-attr> <apt-pkgs> <brew-formula> <apk-pkgs>: the apt
+# pkg_install <nix-attr> <apt-pkg> <brew-formula> <apk-pkg>
-# and apk arguments may each list several packages, separated by spaces.
 pkg_install() {
     detect_pkgmgr
     case "$PKGMGR" in
@@ -75,10 +74,10 @@ pkg_install() {
                 $SUDO env DEBIAN_FRONTEND=noninteractive apt-get update
                 APT_UPDATED=1
             fi
-            $SUDO env DEBIAN_FRONTEND=noninteractive apt-get install -y $2
+            $SUDO env DEBIAN_FRONTEND=noninteractive apt-get install -y "$2"
             ;;
         brew) brew install "$3" ;;
-        apk) apk add --no-cache $4 ;;
+        apk) apk add --no-cache "$4" ;;
     esac
 }
 
@@ -254,12 +253,6 @@ main() {
 
     if missing make; then pkg_install gnumake make make make; fi
     if missing git; then pkg_install git git git git; fi
-    # The race detector in make test needs cgo, which Go turns on only
-    # when it finds its C compiler, gcc on Linux. apt and apk ship the C
-    # library headers apart from gcc.
-    if missing gcc; then
-        pkg_install gcc "gcc libc6-dev" gcc "gcc musl-dev"
-    fi
 
     ensure_node
     ensure_yarn

script/frontend-test

@@ -1,14 +1,13 @@
 #!/bin/sh
-# script/frontend-test: run the frontend test suite: the unit tests in
+# script/frontend-test: run the frontend test suite. The frontend has no
-# test/unit/ with Node's built-in test runner, then the production
+# unit tests; the production build serves as the test (fails on broken
-# build, which fails on broken code.
+# code).
 set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
 
 main() {
     cd "$ROOT"
-    timeout 30 node --test test/unit/*.test.js
     timeout 30 yarn build
 }
 

src/main.js

@@ -1,14 +1,14 @@
+import "./styles.css";
+
 // --- Configuration -----------------------------------------------------------
 
-// Timing, axis labels, and display constants. A target check times out
+// Timing, axis labels, and display constants. Latency above maxLatency is
-// after requestTimeout, 80% of updateInterval, so a round's checks have
+// clamped to "unreachable". The sparkline Y-axis is capped at
-// all finished before the next round is due; latency above maxLatency is
-// recorded as a timeout. The sparkline Y-axis is capped at
 // graphMaxLatency — values above it pin to the top of the chart but still
 // display their real value in the latency figure. The history buffer holds
 // maxHistoryPoints samples (historyDuration / updateInterval).
 // reportInterval is how often collected samples are POSTed to the backend.
-export const CONFIG = {
+const CONFIG = {
     updateInterval: 3000,
     maxHistoryPoints: 100,
     reportInterval: 60000,
@@ -16,7 +16,7 @@ export const CONFIG = {
         return (this.maxHistoryPoints * this.updateInterval) / 1000;
     },
     get requestTimeout() {
-        return this.updateInterval * 0.8;
+        return Math.min(this.updateInterval - 100, 3000);
     },
     get maxLatency() {
         return this.requestTimeout;
@@ -503,16 +503,12 @@ class Reporter {
 
 // --- Latency Measurement -----------------------------------------------------
 
-// Checks one target. The check times out after CONFIG.requestTimeout; the
+async function measureLatency(url) {
-// caller can give it up sooner through the optional signal, which also ends
-// it as a timeout.
-export async function measureLatency(url, signal) {
     const controller = new AbortController();
     const timeoutId = setTimeout(
         () => controller.abort(),
         CONFIG.requestTimeout,
     );
-    signal?.addEventListener("abort", () => controller.abort());
 
     const targetUrl = new URL(url);
     targetUrl.searchParams.set("_cb", Date.now().toString());
@@ -1105,7 +1101,7 @@ function sortAndRebuildWAN(state) {
 
 // --- Main Loop ---------------------------------------------------------------
 
-async function tick(state, signal, onOffline) {
+async function tick(state, onOffline) {
     const ts = Date.now();
 
     if (state.paused) {
@@ -1127,12 +1123,11 @@ async function tick(state, signal, onOffline) {
     log.debug(`Tick #${state.tickCount + 1} started`);
 
     const results = await Promise.all(
-        state.allHosts.map((h) => measureLatency(h.url, signal)),
+        state.allHosts.map((h) => measureLatency(h.url)),
     );
 
-    // User may have paused, or the next round may have given up this
+    // User may have paused while awaiting results — discard them
-    // one's checks, while awaiting results — discard them
+    if (state.paused) return;
-    if (state.paused || signal.aborted) return;
 
     state.tickCount++;
 
@@ -1173,10 +1168,9 @@ async function tick(state, signal, onOffline) {
 
 // --- Recovery Probe ----------------------------------------------------------
 
-// When offline, check 4 random WAN hosts every 500ms, giving up the checks
+// When offline, rapidly poll 4 random WAN hosts every 500ms. As soon as any
-// started 500ms before, so at most 4 are ever waiting. As soon as one
+// responds, stop probing and fire a normal tick to refresh all hosts.
-// answers, stop probing and start a new round at once.
+function startRecoveryProbe(state, triggerTick) {
-function startRecoveryProbe(state, startRounds) {
     if (state._recoveryProbeId) return; // already running
     const candidates = [...state.wan];
     for (let i = candidates.length - 1; i > 0; i--) {
@@ -1187,18 +1181,15 @@ function startRecoveryProbe(state, startRounds) {
     log.notice(
         `Recovery probe started (${canaries.map((h) => h.name).join(", ")})`,
     );
-    state._recoveryProbeId = setInterval(() => {
+    state._recoveryProbeId = setInterval(async () => {
         if (state.paused) return;
-        state._recoveryProbeChecks?.abort();
+        const results = await Promise.all(
-        const checks = new AbortController();
+            canaries.map((h) => measureLatency(h.url)),
-        state._recoveryProbeChecks = checks;
+        );
-        for (const host of canaries) {
+        if (results.some((r) => r.error === null)) {
-            measureLatency(host.url, checks.signal).then((r) => {
-                if (r.error !== null || checks.signal.aborted) return;
             log.notice("Recovery probe: connectivity detected");
             stopRecoveryProbe(state);
-                startRounds();
+            triggerTick();
-            });
         }
     }, 500);
 }
@@ -1207,7 +1198,6 @@ function stopRecoveryProbe(state) {
     if (state._recoveryProbeId) {
         clearInterval(state._recoveryProbeId);
         state._recoveryProbeId = null;
-        state._recoveryProbeChecks?.abort();
     }
 }
 
@@ -1384,34 +1374,18 @@ async function init() {
     updateClocks();
     setInterval(updateClocks, 1000);
 
-    // Rounds never overlap: a round first gives up the last round's checks
-    // if they are still waiting, and the last round then records nothing.
-    // At a steady interval they never are, as they time out at 80% of it;
-    // they can be when a round starts early, after an interval change or
-    // when the recovery probe finds a target answering.
-    let roundChecks = new AbortController();
     function doTick() {
-        roundChecks.abort();
+        tick(state, () => startRecoveryProbe(state, doTick));
-        roundChecks = new AbortController();
-        tick(state, roundChecks.signal, () =>
-            startRecoveryProbe(state, startRounds),
-        );
     }
 
-    // Starts a round now and then one every CONFIG.updateInterval.
-    let tickIntervalId;
-    function startRounds() {
-        clearInterval(tickIntervalId);
     doTick();
-        tickIntervalId = setInterval(doTick, CONFIG.updateInterval);
+    let tickIntervalId = setInterval(doTick, CONFIG.updateInterval);
-    }
-
-    startRounds();
 
     document
         .getElementById("interval-select")
         .addEventListener("change", (e) => {
             const newInterval = parseInt(e.target.value, 10);
+            clearInterval(tickIntervalId);
             CONFIG.updateInterval = newInterval;
             log.notice(
                 `Interval changed to ${humanDuration(newInterval / 1000)}, history reset`,
@@ -1460,7 +1434,8 @@ async function init() {
 
             // Start immediately with new interval
             stopRecoveryProbe(state);
-            startRounds();
+            doTick();
+            tickIntervalId = setInterval(doTick, CONFIG.updateInterval);
         });
 
     window.addEventListener("resize", () => handleResize(state));
@@ -1469,7 +1444,7 @@ async function init() {
 
 // Bootstrap only when loaded as the page: a real DOM containing the #app
 // mount point this module renders into. Importing the module in a unit test
-// (which has no #app) runs nothing, so its exports can be tested in isolation.
+// (which has no #app) runs nothing, so buildReport can be tested in isolation.
 if (typeof document !== "undefined" && document.getElementById("app")) {
     if (document.readyState === "loading") {
         document.addEventListener("DOMContentLoaded", init);

test/unit/main.test.js

@@ -1,66 +0,0 @@
-// Unit tests for src/main.js, run by script/frontend-test with Node's
-// built-in test runner. Importing the module does not start the page.
-
-import { test } from "node:test";
-import assert from "node:assert/strict";
-import { CONFIG, measureLatency } from "../../src/main.js";
-
-// measureLatency writes timeouts to the debug log, which looks for its
-// panel in the page. There is no page here.
-globalThis.document = { getElementById: () => null };
-
-// Mocks the clock for test t, so that a check lasting seconds takes no real
-// time, and replaces fetch with a target that answers after answerAfter
-// milliseconds of that clock, or never when answerAfter is Infinity. Both
-// are restored when the test ends.
-function mockTarget(t, answerAfter) {
-    t.mock.timers.enable({ apis: ["setTimeout", "Date"] });
-    t.mock.method(performance, "now", () => Date.now());
-    t.mock.method(
-        globalThis,
-        "fetch",
-        (url, { signal }) =>
-            new Promise((resolve, reject) => {
-                if (answerAfter !== Infinity) setTimeout(resolve, answerAfter);
-                signal.addEventListener("abort", () => reject(signal.reason));
-            }),
-    );
-}
-
-// The result of check if it has ended, otherwise "still waiting".
-function settled(check) {
-    return Promise.race([
-        check,
-        new Promise((resolve) => setImmediate(resolve, "still waiting")),
-    ]);
-}
-
-for (const interval of [10000, 30000]) {
-    const timeout = interval * 0.8;
-    // Over 3 seconds, which the timeout used to be capped at.
-    const slowAnswer = timeout - 1000;
-
-    test(`at a ${interval}ms interval, an answer after ${slowAnswer}ms is recorded with its real time`, async (t) => {
-        CONFIG.updateInterval = interval;
-        mockTarget(t, slowAnswer);
-        const check = measureLatency("https://target.test");
-        t.mock.timers.tick(slowAnswer);
-        assert.deepEqual(await settled(check), {
-            latency: slowAnswer,
-            error: null,
-        });
-    });
-
-    test(`at a ${interval}ms interval, a target that never answers is recorded as a timeout after ${timeout}ms`, async (t) => {
-        CONFIG.updateInterval = interval;
-        mockTarget(t, Infinity);
-        const check = measureLatency("https://target.test");
-        t.mock.timers.tick(timeout - 1);
-        assert.equal(await settled(check), "still waiting");
-        t.mock.timers.tick(1);
-        assert.deepEqual(await settled(check), {
-            latency: null,
-            error: "timeout",
-        });
-    });
-}