AC Coverage Assistant | AC 覆蓋率助手

Analyze Acceptance Criteria (AC) to test traceability and generate coverage reports.

分析驗收條件（AC）與測試之間的追蹤關係，並產生覆蓋率報告。

What This Does vs /coverage | 與 /coverage 的區別

Aspect	/coverage	/ac-coverage
Scope	Code-level (line/branch/function)	Requirement-level (AC-to-test)
Input	Source code + test runner	SPEC file + test annotations
Question	"How much code is tested?"	"Which AC have tests?"
Output	Coverage percentages	Traceability matrix + gap report

Workflow | 工作流程

1. Parse SPEC — Extract AC definitions (AC-1, AC-2, ...) from the specification file
2. Scan Tests — Search test files for @AC and @SPEC annotations using standard linking conventions
3. Build Matrix — Map each AC to its test references (file, test name, line)
4. Classify Status — Mark each AC as ✅ covered, ⚠️ partial, or ❌ uncovered
5. Calculate Coverage — Apply formula: Coverage % = (covered + partial × 0.5) / total × 100
6. Generate Report — Output standardized Markdown report

Linking Convention | 標註慣例

Tests MUST reference their source AC using standard annotations:

// TypeScript/JavaScript
describe('AC-1: User login with valid credentials', () => {
  // @AC AC-1
  // @SPEC SPEC-001
  it('should redirect to dashboard on successful login', () => { ... });
});

# Python
class TestAC1_UserLogin:
    """AC-1: User login with valid credentials
    @AC AC-1
    @SPEC SPEC-001
    """
    def test_redirect_to_dashboard(self): ...

# BDD Feature
@SPEC-001 @AC-1
Scenario: User login with valid credentials

Coverage Thresholds | 覆蓋率門檻

Threshold	Default Value	Enforcement
Check-in	80%	Required for feature branch merge
Release	100%	Required for production release
Warning	60%	Triggers coverage warning

Thresholds are configurable via --threshold parameter or project configuration.

Four-Layer Traceability | 四層追溯（--full 模式）

Use --full flag to extend from 2-layer (AC→Test) to 4-layer traceability.

使用 --full 標記將追溯從 2 層（AC→Test）擴展為 4 層。

Traceability Layers | 追溯層次

Layer 0: Requirement / User Story (REQ)
    ↓ (defines)
Layer 1: Acceptance Criteria (AC)
    ↓ (@AC annotations)
Layer 2: Test Cases
    ↓ (covers)
Layer 3: Source Code (@implements)

Layer Annotations | 各層標註慣例

// Layer 3→1: Code referencing AC
// @implements AC-1, AC-2
function authenticate(user: string, pass: string) { ... }

<!-- Layer 0→1: Requirement in SPEC -->
## Requirements
### REQ-1: User Authentication
- AC-1: Given valid credentials, when login, then authenticated
- AC-2: Given invalid credentials, when login, then rejected

Full Traceability Report | 完整追溯報告

## Four-Layer Traceability Matrix

| Requirement | AC | Test | Code | Status |
|-------------|-----|------|------|--------|
| REQ-1 | AC-1 | auth.test.ts:15 | auth.ts:42 | ✅ Full |
| REQ-1 | AC-2 | auth.test.ts:30 | auth.ts:58 | ✅ Full |
| REQ-2 | AC-3 | — | dashboard.ts:10 | ⚠️ No test |
| REQ-3 | AC-4 | export.test.ts:5 | — | ⚠️ No code |

### Gap Summary
- Layer 0→1: 2 requirements without AC
- Layer 1→2: 1 AC without tests
- Layer 2→3: 0 tests without code mapping
- Layer 3→1: 3 code files without AC mapping

Reverse Tracing | 反向追溯

Use --trace-code <path> to trace from code back to requirements.

使用 --trace-code <path> 從程式碼反向追溯到需求。

/ac-coverage --trace-code src/auth.ts
# Output:
# src/auth.ts:42 → @implements AC-1 → REQ-1 (SPEC-AUTH-001)
# src/auth.ts:58 → @implements AC-2 → REQ-1 (SPEC-AUTH-001)

Report Format | 報告格式

The generated report follows the standard format from core/acceptance-criteria-traceability.md:

# AC Coverage Report

**Specification**: SPEC-001 — Feature Name
**Generated**: 2026-03-18
**Coverage**: 75% (6/8 AC)

## Summary

| Status | Count | Percentage |
|--------|-------|------------|
| ✅ Covered | 5 | 62.5% |
| ⚠️ Partial | 2 | 25.0% |
| ❌ Uncovered | 1 | 12.5% |

## Traceability Matrix

| AC-ID | Description | Status | Test Reference |
|-------|-------------|--------|----------------|
| AC-1 | Login with valid credentials | ✅ | auth.test.ts:15 |
| AC-2 | Reject invalid credentials | ✅ | auth.test.ts:32 |
| ...   | ...                        | ... | ... |

## Gaps
- **AC-8**: Social login — Blocked by OAuth sandbox

## Action Items
1. [ ] AC-8: Set up OAuth sandbox (ETA: TBD)

Next Steps Guidance | 下一步引導

After /ac-coverage completes, the AI assistant should suggest:

AC 覆蓋率分析完成。建議下一步 / AC coverage analysis complete. Suggested next steps:

• 覆蓋率達標 → 執行 /checkin 品質關卡 — Coverage meets threshold → Run /checkin quality gates
• 有未覆蓋 AC → 執行 /derive-tdd 補齊測試 ⭐ Recommended / 推薦 — Uncovered AC found → Run /derive-tdd to add tests
• 有部分覆蓋 AC → 檢查缺少的邊界情況 — Partial AC → Review missing edge cases
• 需要完整追溯 → 執行 /ac-coverage --full — Need full traceability → Run with --full
• 反向追溯 → 執行 /ac-coverage --trace-code <path> — Reverse trace → Use --trace-code

Reference | 參考

• Core standard: acceptance-criteria-traceability.md
• SPEC: SPEC-AC-COVERAGE.md
• Related: test-coverage-assistant (code-level coverage)
• Related: checkin-assistant (quality gates)

AI Agent Behavior | AI 代理行為

完整的 AI 行為定義請參閱對應的命令文件：/ac-coverage

For complete AI agent behavior definition, see the corresponding command file: /ac-coverage