v1.91.9.0 feat: test value bar in plan-eng-review, review, qa and ship, plus /test-audit (#2998)

review/specialists/testing.md

@@ -80,3 +80,68 @@ red tests. Unit tests suit logic; real integration/E2E tests protect boundaries
 - New public methods/functions with zero test coverage
 - Changed methods where existing tests only cover the old behavior, not the new branch
 - Utility functions called from multiple places but tested only indirectly
+- A path whose only tests are weak (★ smoke/existence/trivial, or a new test failing the
+  authoring gate below) stays a coverage gap at its existing severity; a low-value test
+  never closes a gap
+
+### Low-value or implementation-coupled tests
+Scope: tests and test-only production seams added or changed in the diff. Findings are
+INFORMATIONAL, never CRITICAL, and never an auto-delete: recommend rewrite at the owning
+boundary, extend an existing test, or retire with a complete retirement card
+(`test, detects, non_test_callers, search_command, stronger_proof, history, unlocks,
+validation`). End each finding's `fix` with `Repo-wide sweep: run /test-audit.`
+
+A new or changed test passes the authoring gate only when all four answers exist (read
+its `Value: protects=...; fails_when=...; why_new=...; seam=...` header comment when the
+diff has one):
+1. What observable behavior, invariant or independent contract does it protect?
+2. What credible regression makes it fail?
+3. Why does existing coverage not already catch that? Prefer adding a row to an existing table-driven test or shared fixture over a near-duplicate.
+4. Does it need a production seam (export, flag, wrapper, injection hook) that no production caller needs? If yes, test at the real boundary instead.
+
+Patterns:
+- assertion-free coverage probes
+- self-comparisons and identity copies
+- copied fixtures, inventories or export lists
+- exact source, import or string greps that are not a declared contract
+- private predicate or call-shape tests duplicated at a real boundary
+- duplicate invocations of the same contract
+- per-caller replays of a shared helper's tests
+- tests whose only purpose is keeping a test-only export, global or wrapper alive
+- production code whose only callers are tests
+
+Retention bar (never flag): a test that independently enforces a public API, protocol,
+config, migration, storage, security, platform, default, prompt-byte, generated-output
+(SKILL.md golden), package, release or architecture contract; call order when order is
+observable; source inspection when it is the cheapest independent guard; anything
+reachable from the package entrypoint (`package.json` exports/main, index re-exports).
+Static or slow is not a reason to delete.
+
+Evidence for each finding goes in `evidence` with the fields `detects` (what failure the
+test can actually detect), `non_test_callers`, `search_command` and `stronger_proof`.
+For the last two patterns, run the caller check for each symbol the diff adds or exports,
+only when the symbol matches `^[A-Za-z_][A-Za-z0-9_]*$` (otherwise record "caller check
+unavailable: unsupported symbol"), with the symbol quoted, never interpolated unquoted:
+
+```bash
+git grep -n -F -w -e '<symbol>' -- . ':!test/' ':!tests/' ':!spec/' ':!**/__tests__/**' ':!**/*.test.*' ':!**/*.spec.*' ':!**/*_test.*' ':!**/test_*.py'
+```
+
+Record the command, exclusions and hit count, and mark the evidence "grep-only" (it cannot
+see re-exports, dynamic dispatch or generated code). If the search fails, record: caller
+check unavailable: <command>. The finding stays INFORMATIONAL and nothing is proposed for
+deletion; run the search by hand to complete the evidence. (see
+~/.claude/skills/gstack/docs/test-value-bar.md#caller-check-unavailable)
+
+Skip a test carrying `gstack:test-value keep reason="<why>"` (any comment syntax). Report
+the count and reasons of skipped tests as one INFORMATIONAL line.
+
+Rejection vocabulary, when a finding names why a new test fails the gate:
+`duplicate_protects`, `needs_seam`, `incomplete_card`, `no_credible_regression`,
+`covered_elsewhere`, `implementation_coupled`.
+
+### Regression test without red proof
+- The diff adds a test named or commented as a regression, and neither the commit history
+  nor the PR body shows it failing before the fix. A regression test that never
+  demonstrably failed proves the mock, not the fix. INFORMATIONAL; ask for the
+  fails-at-HEAD / passes-after-fix record.