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test: disable Go's test cache so every run queries live DNS (closes #139)
`script/test` did not pass `-count=1`, so on an unchanged tree Go
served the whole suite from its test cache: exit 0 in ~0.2s with every
package marked `(cached)` and not one DNS query made. This repo's suite
exists to exercise live resolution on every run (`TESTING.md`), so that
green asserted nothing — and it is exactly the green used as evidence
that a flakiness fix works, since "run it a few times" stops being
runs after the first.

`-count=1` now disables caching on every invocation.

The conditional verbose rerun that `REPO_POLICIES.md` mandates was
missing at the same spot and is added here rather than left broken: the
primary run had been unconditionally `-v`, which is the failure mode
the policy exists to prevent (unreadable CI and `docker build` logs on
success). Tests now run quiet, and only a failure triggers the `-v`
rerun. The rerun carries `-count=1` too, so it cannot replay a cached
copy of the failure it is meant to diagnose, and its exit status is
discarded in favour of a forced 1: the first failure already proved the
suite broken, so a flake that passes the second time must not turn the
build green.

`-timeout 90s` is untouched. It is a deliberate backstop that must
strictly exceed the 60s hard cap on suite duration.

No special-casing for the Docker build, which also reaches this script
via `RUN make test`: a fresh container's test cache is empty, so
`-count=1` changes nothing there and carving out an exception would
only create a second code path that could drift.

Verified: three back-to-back `make test` runs on an unchanged tree,
zero `(cached)` markers, ~4.0-4.5s wall each (was ~0.2s cached),
comfortably inside the 20s target with `-race` and `-cover` both still
working and coverage percentages unchanged. The rerun-and-still-fail
path was exercised against a purpose-built flaky test that fails once
then passes: quiet failure, verbose rerun that genuinely re-executed,
exit 1 regardless. `make check` green.
2026-08-10 13:48:15 +00:00

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# Testing Policy
## DNS Resolution Tests
All resolver tests **MUST** use live queries against real DNS servers.
No mocking of the DNS client layer is permitted.
### Rationale
The resolver performs iterative resolution from root nameservers through
the full delegation chain. Mocked responses cannot faithfully represent
the variety of real-world DNS behavior (truncation, referrals, glue
records, DNSSEC, varied response times, EDNS, etc.). Testing against
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 within the 60-second target
- Query timeout is calibrated to 3× maximum antipodal RTT (~300ms)
plus processing margin
- Root server fan-out is limited to reduce parallel query load
- 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 `DNSClient`** for resolver tests (the mock constructor
exists for unit-testing other packages that consume the resolver)
- **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