Nyquist — Test-to-Requirement Coverage Mapping

Maps plan acceptance criteria to test files. Identifies coverage gaps where requirements exist but no corresponding test validates them.

When to Use

• Phase 2 (Test): After tester writes initial tests, verify all acceptance criteria are covered
• Phase 4 (Review): As part of test coverage dimension, verify no gaps
• User says "check test coverage", "are all requirements tested", "coverage gaps"
• Before Gate 2: verify implementation matches plan

Workflow

1. Load plan — Read tasks/plans/YYMMDD-name/plan.md, extract acceptance criteria
2. Scan tests — Glob for test files (**/*.test.*, **/*.spec.*, **/test_*.*)
3. Map criteria → tests — For each acceptance criterion, search test descriptions/names for matching keywords
4. Identify gaps — Criteria with no matching test = coverage gap
5. Produce report — Structured output with mapping table and gap list

Output Format

## Nyquist Coverage Report: [Plan Name]

### Requirement-to-Test Mapping

| # | Acceptance Criterion | Test File | Test Name | Status |
|---|---------------------|-----------|-----------|--------|
| 1 | [criterion text] | src/auth.test.ts | "should authenticate user" | COVERED |
| 2 | [criterion text] | — | — | GAP |
| 3 | [criterion text] | src/api.test.ts | "returns 404 for missing" | COVERED |

### Coverage Summary

- **Total criteria:** N
- **Covered:** N (N%)
- **Gaps:** N

### Gap Details

1. **[criterion text]** — No test found. Suggested test: [brief description]
2. **[criterion text]** — No test found. Suggested test: [brief description]

### Recommendation

[PASS — all criteria covered | WARN — N gaps found, suggest adding tests]

Matching Strategy

• Keyword matching: Extract key nouns/verbs from acceptance criteria, search in test describe/it/test strings
• File path matching: If criterion mentions "auth", search in **/auth*test*
• Fuzzy matching: If exact match fails, check for semantic equivalents (e.g., "login" ≈ "authenticate")
• Manual override: If no match found, ask user to confirm the gap is real (not a naming mismatch)

Gotchas

What This Skill Does NOT Do

• Does NOT write tests — that's the tester agent's job
• Does NOT modify plan files — read-only analysis
• Does NOT replace manual review of test quality — only checks existence, not correctness
• Does NOT run tests — only reads test file contents