go-testing

Idiomatic Go testing with the stdlib `testing` package and the go-testdeep assertion library. ALWAYS use this skill when writing or reviewing Go tests — table-driven tests with `map[string]testCase`, `t.Run` subtests, `t.Helper()` for assertion helpers, `t.Cleanup`, `t.Parallel`, integration test gating with environment variables, benchmarks (`testing.B`), fuzz tests, go-testdeep operators (`td.Cmp`, `td.CmpError`, `td.CmpNoError`, `td.Struct`, `td.Smuggle`, `td.Between`, `td.Re`, `td.Require`), and the third-party-frameworks debate (go-testdeep when deps are allowed, stdlib-only for dependency-free projects, never testify). Pair with go-sql for testing DB code with sqlc's `Querier` interface, go-http for `httptest` patterns, and go-concurrency for race-detector usage.