tdd

# AL Test Development Patterns

## Planning Test Work

When planning any test-related task, structure your plan with Red-Green-Refactor phases:

### Plan Structure

**Phase 1 - Red (Design):**
- Identify test scenarios to cover
- Plan DEBUG-* telemetry checkpoints for verification
- Determine which code paths need proof of execution

**Phase 2 - Green (Implementation):**
- Write test code with DEBUG-TEST-START markers
- Add DEBUG-* checkpoints in production code at decision points
- Run tests and verify telemetry.jsonl shows correct paths

**Phase 3 - Refactor (Cleanup):**
- Remove ALL DEBUG-* telemetry from test and production code
- Verify zero DEBUG-* calls remain

### TodoWrite Integration

When implementing tests, create todos for each phase:

```
1. [Red] Add DEBUG-TEST-START to <TestName>
2. [Red] Add DEBUG-BRANCH-* checkpoints to <ProductionCode>
3. [Green] Run al-build and verify test passes
4. [Green] Verify correct path in telemetry.jsonl
5. [Refactor] Remove DEBUG-* from production code
6. [Refactor] Remove DEBUG-TEST-START from test code
7. [Refactor] Verify zero DEBUG-* calls remain
```

This structure ensures every test task follows the complete verification cycle.

## DEBUG Telemetry is Always Temporary

**Expected starting state:** Zero `DEBUG-*` telemetry calls in both production code (`app/src/`) and test code (`test/src/`).

**Why:** DEBUG telemetry is temporary scaffolding for proving code paths during development. It is NOT production instrumentation. If you find existing DEBUG-* calls, they indicate incomplete previous work.

**Lifecycle:**
1. Start clean (expect no DEBUG-* anywhere)
2. Add DEBUG-* calls during Red phase to prove execution
3. Verify in telemetry.jsonl during Green phase
4. **Remove ALL DEBUG-* calls during Refactor phase** (REQUIRED)
5. End clean (no DEBUG-* anywhere)

**If you find existing DEBUG-* calls:**
- Complete the previous work (remove them after verification), OR
- Remove them immediately if they're orphaned from aba