go-test-review

Go Test Review

Purpose

Audit Go test code for quality and coverage effectiveness. Reviews HOW tests are written — not the production code being tested.

This skill is conditionally triggered — only when _test.go files are in the diff. If a PR has only implementation code with no tests, this skill may suggest "missing test coverage" but does not deep-dive.

This skill does NOT cover: security, concurrency, performance, quality, error handling, or logic of production code — those belong to sibling vertical skills.

When To Use

• PR contains _test.go files
• Code uses httptest, testing.B, testing.F
• Code includes testdata/ directory changes
• Need to evaluate test coverage

When NOT To Use

• Reviewing production code security/performance/logic → use corresponding sibling skill
• Only implementation code changed, no tests → may note "missing tests" but no deep review

Mandatory Gates

1) Go Version Gate

Read go.mod. Key version gates:

Feature	Minimum Go	Caveat
t.Setenv	1.17	Cannot combine with t.Parallel() — panics on every Go version (process-wide env)
Fuzz testing (testing.F)	1.18
Loop variable fix	1.22	Affects t.Parallel() + loop variable capture
t.Chdir	1.24	Added 1.24; like t.Setenv, panics if combined with t.Parallel()

2) Anti-Example Suppression Gate

MUST quote specific evidence. Category match alone insufficient.

Embedded anti-examples:

• "Testing standard library behavior" — test that json.Marshal produces valid JSON, or that strings.Contains works. These test Go's stdlib, not your code.
• "Test only asserts err == nil" — BUT: do NOT flag if function genuinely has no meaningful return value (void-like operations where error is the only output, e.g., Close(), Flush()).
• "Should use integration test" — when unit test with mock is the correct choice for fast, isolated testing. Not every test needs a real database.
• "Missing test for unexported function" — when function is simple helper fully covered by exported function tests.
• "Missing benchmark" — when code is not on a hot path and benchmarking provides no actionable insight.