Plan Test Coverage

Test Coverage Audit + Plan (User-Story-Driven)

Degree of freedom: MIXED — story derivation and fake-green judgment are HIGH; coverage commands run exactly. Stay plan-only. No tests written in this pass.

Role: Senior QA / test engineer.

Task: Audit the test suite against user stories and critical flows, not just line %. Find untested, weakly tested, and fake-green tests. Build traceability matrix + burndown. Audit & plan only — do not write tests in this pass.

This skill vs neighbors

Loop position: plan-stub-checker → wiring approval → plan-test-coverage → plan-perf-audit / plan-security-audit → plan-docs-sync

How to reason (every plan item)

1. Propose — the given/when/then spec for a gap or a fake-green replacement
2. Risk — critical flow ships untested, or a green suite that cannot fail
3. Keep-working — stories that already have honest, asserting tests
4. Phase — Critical+fake-green → Error-edge → Important → Minor (do not execute)

Worked example

Propose: add an e2e for "authed user exports data" covering the newly wired Settings control; replace expect(true).toBe(true) in export.test.ts. Risk: stub-checker wired the button; coverage % is 82 but the critical path has no test — fake-green hides it. Keep-working: login happy-path Playwright spec already asserts a session cookie. Phase: Phase 1 — Critical uncovered + fake-green. Spec: given authed session / when Export clicked / then POST /api/export 200 and a file download.

⛔ Preservation Contract

Read references/preservation-contract.md. Acknowledge in output #1.

References

Phase flow

0. Derive user stories from code (FIRST)
1. Inventory existing tests + coverage baseline
2. Traceability matrix (story ↔ test)
3. Multi-lens coverage audit
4. Fake-green / weak-test detection
5. Burndown + phased coverage plan
6. Guardrails (mutation CI, coverage ratchet)
7. Research citations

Detail: references/methodology.md

Phase 0 — Stories from code (before judging coverage) [HIGH freedom]

Reconstruct what the app promises from routes, handlers, flows — not invented stories.

Each story: acceptance criteria + criticality + cited implementing code.

Phase 1 — Test inventory [LOW freedom — run exactly]

Discover test files; map to stories. Run coverage tool if available:

npm test -- --coverage
npx vitest run --coverage

Not run → [NEEDS RUN] with command to run.

Phase 2 — Traceability matrix [HIGH freedom]

Core artifact. Every critical story with no test = top-priority gap.

Template: references/output-templates.md

Phase 3–4 — Depth + fake-green [HIGH freedom]

Judge branch/path/risk/integration/error paths — not just line %.

Flag fake-green: over-mocks, expect(true), implementation-detail tests.

Recommend mutation testing on critical modules for blind spots.

Burndown + plan [HIGH freedom — plan only]

Phases:

1. Critical uncovered + fake-green (especially newly wired stubs from stub-checker)
2. Error/edge + integration boundaries
3. Important stories
4. Minor branches

Per gap: given/when/then spec + "what must keep working". Plan only.

Self-critique before the burndown [LOW freedom — do not skip]

1. evidenced-not-assumed — stories cited from routes/handlers; coverage numbers from a real run or [NEEDS RUN]
2. plan-only — no tests written, deleted, or skipped
3. severity/phase justified — untested critical stories and fake-green outrank line-% gaps
4. right-owner — mutation score / assertion theater → test-mutation; writing tests → test-unit / test-playwright; unwired UI → plan-stub-checker
5. no-false-safety — coverage % is not depth; never invent stories or counts

Required output (in order)

1. Preservation-contract acknowledgment
2. Derived user stories + AC + criticality (cited)
3. Existing-test inventory + baseline or [NEEDS RUN]
4. Traceability matrix
5. Multi-lens coverage audit
6. Fake-green / weak-test findings
7. Burndown table
8. Coverage + enhancement plan, phased
9. Guardrails/tooling
10. Research notes + citations
11. Open questions / [NEEDS PRODUCT INPUT] / [NEEDS RUN]

Rules

• Plan only — do not write tests until approved.
• User stories first, from real code.
• Coverage ≠ single %. Judge depth + mutation honesty.
• Never fabricate stories, tests, or numbers.
• Separate true gap vs test-quality issue.