NO PRODUCTION CODE WITHOUT A FAILING TEST FIRST

RED:    Write a failing test
        → Run it
        → Confirm it FAILS
        → If it passes immediately → ERROR (invalid test)

GREEN:  Write minimal code to pass
        → Only enough to make the test pass
        → No extra features
        → No "while I'm here" additions

REFACTOR: Clean up
        → Keep tests green
        → Improve structure
        → Remove duplication

TASKS.md Phase 2 (Tests):
  - Write contract tests
  - Write integration tests
  - Write unit tests
  - Run all tests → ALL MUST FAIL

⚠️ TEST VERIFICATION CHECKPOINT:
  → Run: npm test (or equivalent)
  → Expected: All new tests FAIL
  → If any test passes immediately → STOP
  → Passing test = invalid test or code already exists

TASKS.md Phase 3 (Implementation):
  - Implement to make tests pass
  - One test at a time
  - Minimal code only

After each implementation:
  → Run tests
  → Verify previously failing test now passes
  → Verify no regressions

Option A: DELETE AND RESTART (Recommended)
  1. Delete the implementation code
  2. Keep only the interface/contract
  3. Write failing tests
  4. Re-implement with TDD

Option B: WRITE TESTS THAT FAIL FIRST
  1. Comment out the implementation
  2. Write tests
  3. Run tests → verify they fail
  4. Uncomment implementation
  5. Run tests → verify they pass

NEVER: Keep code and write passing tests
  → This is "testing after" disguised as TDD
  → Tests that pass immediately prove nothing

Good Tests:
  ✅ Test behavior, not implementation
  ✅ Use realistic data
  ✅ Cover edge cases
  ✅ Independent (no shared state)
  ✅ Fast (< 1 second each)
  ✅ Descriptive names

Bad Tests (Cheater Tests):
  ❌ assert True
  ❌ assert result is not None
  ❌ Mock everything, test nothing
  ❌ Test implementation details
  ❌ Depend on execution order

Error Recording Workflow:
  1. Capture Error Context:
     - Phase (flow-dev / T###)
     - Error Type (Test Failure | Build Error | Runtime Error)
     - Full error message
     - Timestamp

  2. Create ERROR_LOG.md if not exists:
     → Use .claude/docs/templates/ERROR_LOG_TEMPLATE.md
     → Location: devflow/requirements/${REQ_ID}/ERROR_LOG.md

  3. Append Error Record:
     ## [TIMESTAMP] E###: TITLE
     **Phase**: flow-dev / T###
     **Error Type**: Test Failure
     **Error Message**:
     ```
     [完整错误信息]
     ```
     **Root Cause**: [分析后填写]
     **Resolution**: [解决后填写]
     **Prevention**: [可选]

  4. Debug with Error Context:
     → Read ERROR_LOG.md for similar past errors
     → Apply attention refresh (Protocol 4)
     → Fix the root cause, not symptoms

  5. Update Record After Fix:
     → Fill Root Cause
     → Fill Resolution
     → Add Prevention if applicable

## [2026-01-08T14:30:00] E001: Test Failure - User Login Validation

**Phase**: flow-dev / T005
**Error Type**: Test Failure
**Error Message**:
\`\`\`
FAIL src/auth/login.test.ts
  × should reject invalid email format
    Expected: false
    Received: true
\`\`\`

**Root Cause**: 正则表达式 `/^.+@.+$/` 过于宽松，接受了 `user@` 这样的无效邮箱
**Resolution**: 更新正则为 `/^[^\s@]+@[^\s@]+\.[^\s@]+$/` 要求至少有域名和顶级域
**Prevention**: 扩充测试用例，添加边界情况（无域名、无顶级域、特殊字符等）