# Tests Audit Report

**Branch**: fix/timing-based-test-waits
**Base**: main
**Date**: 2025-12-28 22:51:00
**PR**: #44

---

## Executive Summary

This PR systematically replaces timing-based test waits (`setTimeout`) with deterministic event-driven synchronization patterns. The changes are well-executed and improve test reliability by:

1. Replacing arbitrary `setTimeout` delays with `flushEventLoop()` utility
2. Using `vi.spyOn(Date, 'now')` for deterministic timestamp testing
3. Adding event synchronization methods to `TestEventBus`
4. Injecting `TestResourceMonitor` via bootstrap options

**Overall Assessment**: APPROVED - Changes are clean and improve test quality.

---

## Issues in Your Changes (BLOCKING)

**None identified.**

All changes follow established patterns and best practices:
- No new test antipatterns introduced
- Consistent use of `flushEventLoop()` across all modified files
- Date mocking properly cleans up with `mockRestore()`

---

## Issues in Code You Touched (Should Fix)

### Medium Priority

#### 1. Unused synchronization methods in TestEventBus

**File**: `/workspace/delegate/tests/fixtures/test-doubles.ts`
**Lines**: 197-271

The PR adds several synchronization methods to `TestEventBus`:
- `waitFor()` - Used by worker-handler tests
- `flushHandlers()` - Used by worker-handler tests
- `once()` - Required for event-helpers.ts compatibility
- `removeListener()` - Required for event-helpers.ts compatibility

However, the integration tests primarily use the simpler `flushEventLoop()` from `event-helpers.ts`. The `TestEventBus.waitFor()` method duplicates `waitForEvent()` from event-helpers.ts.

**Recommendation**: Document when to use each synchronization method:
- `flushEventLoop()` - For simple event propagation
- `TestEventBus.waitFor()` - For waiting on specific events with filtering
- `waitForEvent()` - For non-TestEventBus implementations

**Severity**: Low - Not blocking, but adds maintenance overhead

#### 2. Worker handler tests use intentional delays for timing verification

**File**: `/workspace/delegate/tests/unit/services/handlers/worker-handler.test.ts`
**Lines**: 896, 940

Two tests in the "Spawn Serialization - TOCTOU Race Prevention" section use `setTimeout` with 15ms delays:

```typescript
// NOTE: This setTimeout simulates real spawn time and is intentional for timing tests
await new Promise(resolve => setTimeout(resolve, 15));
```

These are intentional and documented with comments explaining why they are needed (to verify spawn serialization behavior). The comments make this clear.

**Status**: Acceptable - Intentional use for timing verification tests

---

## Pre-existing Issues (Not Blocking)

### Test Design Patterns

#### 1. Inconsistent wait patterns remain in some tests

While this PR addresses the main offenders, a few edge cases remain:

**File**: `/workspace/delegate/tests/integration/event-flow.test.ts`
**Line**: 229

```typescript
await new Promise(() => {}); // Never resolves
```

This is intentional for testing timeout behavior - not a wait pattern issue.

**Status**: Acceptable

#### 2. TestEventBus.removeListener has simplified implementation

**File**: `/workspace/delegate/tests/fixtures/test-doubles.ts`
**Line**: 264-270

```typescript
removeListener(eventType: string, handler: (data: any) => void): void {
  const handlers = this.handlers.get(eventType);
  if (handlers) {
    // Note: This is a simplified implementation - in tests we typically
    // rely on dispose() for full cleanup rather than individual removal
    handlers.delete(handler as any);
  }
}
```

The comment acknowledges the limitation. This is acceptable for test doubles.

**Status**: Acceptable

---

## Analysis by Category

### Test Coverage

| Aspect | Status | Notes |
|--------|--------|-------|
| New code tested | GOOD | flushEventLoop() and TestEventBus methods are exercised |
| Edge cases | GOOD | Worker handler tests cover serialization edge cases |
| Error paths | GOOD | Timeout and failure scenarios tested |

### Test Quality

| Aspect | Status | Notes |
|--------|--------|-------|
| Test isolation | GOOD | Each test uses fresh fixtures |
| Clear assertions | GOOD | Assertions focus on behavior |
| AAA pattern | GOOD | Arrange-Act-Assert followed |
| Test naming | GOOD | Descriptive test names |

### Test Design

| Aspect | Status | Notes |
|--------|--------|-------|
| Determinism | IMPROVED | Replaced arbitrary delays with event-driven waits |
| Maintainability | GOOD | Centralized wait utilities |
| Flakiness risk | REDUCED | No timing-dependent assertions |

---

## Summary

**Your Changes:**
- CRITICAL: 0
- HIGH: 0
- MEDIUM: 1 (unused sync methods - low impact)

**Code You Touched:**
- HIGH: 0
- MEDIUM: 0

**Pre-existing:**
- MEDIUM: 0
- LOW: 2 (acceptable patterns with documentation)

**Tests Score**: 9/10

The PR makes targeted, effective improvements to test reliability. The addition of `flushEventLoop()` provides a clean abstraction for event synchronization. The Date.now() mocking in domain.test.ts and dependency-repository.test.ts replaces timing-dependent assertions with deterministic ones.

**Merge Recommendation**: APPROVED

---

## Changed Files Analysis

### Production Code (1 file)

| File | Changes | Impact |
|------|---------|--------|
| `src/bootstrap.ts` | Add `resourceMonitor` option | Enables test injection |

### Test Utilities (1 file)

| File | Changes | Impact |
|------|---------|--------|
| `tests/fixtures/test-doubles.ts` | Add sync methods to TestEventBus | Improves test capabilities |

### Test Files (10 files)

| File | Timing Waits Removed | Pattern Used |
|------|---------------------|--------------|
| `tests/integration/event-flow.test.ts` | 8 | flushEventLoop() |
| `tests/integration/service-initialization.test.ts` | 3 | flushEventLoop() |
| `tests/integration/task-dependencies.test.ts` | 24 | flushEventLoop() |
| `tests/integration/worker-pool-management.test.ts` | 9 | flushEventLoop() |
| `tests/unit/core/domain.test.ts` | 1 | vi.spyOn(Date, 'now') |
| `tests/unit/core/events/event-bus-request.test.ts` | 1 | Promise.resolve() |
| `tests/unit/core/result.test.ts` | 2 | Promise.resolve(), removed fake timers |
| `tests/unit/implementations/dependency-repository.test.ts` | 2 | vi.spyOn(Date, 'now') |
| `tests/unit/services/handlers/dependency-handler.test.ts` | 6 | flushEventLoop() |
| `tests/unit/services/handlers/worker-handler.test.ts` | 0 | Already uses waitFor() |

---

## Test Execution Results

```
test:core           273 passed (3.11s)
test:integration     25 passed (3.83s)
test:handlers        43 passed (3.03s)
test:repositories    83 passed (2.12s)
```

All tests pass. No regressions detected.

---

## PR Comments

No blocking issues found. No PR line comments created.

**PR Comments: 0 created, 0 skipped**
