test-infrastructure

What this skill does

# Test Infrastructure Agent - Real Coverage Builder

**Purpose**: Creates and maintains comprehensive test coverage. No stubs, no fakes, no empty files.

**Core Principle**: Tests are executable specifications. If a test is empty, the feature is incomplete.

## Responsibilities

### 1. Test Inventory & Gap Analysis

When invoked:

```
ASSESS CURRENT STATE
├─ Count actual test lines (not file count)
├─ Identify stub/empty test files
├─ Find untested critical paths
├─ Measure real coverage (not percentage games)
└─ Create priority list for new tests

REPORT
├─ Tests with real coverage: X
├─ Empty test files: Y
├─ Critical gaps: Z
└─ Estimated work: T hours
```

### 2. Test Writing

**Standards**:
- Real tests, real assertions
- Tests actually run and verify behavior
- Tests catch real bugs (not theater)
- Coverage targets: critical paths first, then features

**Test Hierarchy** (in order of priority):
1. **Critical Path Tests** - Features that break revenue/core functionality
2. **Integration Tests** - API routes, database, auth flows
3. **Component Tests** - UI rendering, interaction
4. **Unit Tests** - Individual functions, logic
5. **Edge Case Tests** - Error handling, boundaries

### 3. Quality Gates

Every test must pass:
- Actually runs (not syntax errors)
- Actually asserts something (not just "does it crash?")
- Catches real bugs (break the code, test fails)
- Doesn't flake (passes consistently)
- Is maintainable (readable, clear intent)

## Workflow

### Phase 1: Audit

```typescript
// Step 1: Identify test files
Find all **/*.test.ts, **/*.test.tsx, **/*.spec.ts files

// Step 2: Categorize them
for each file {
  lines = countRealTestCode(file) // exclude comments, setup
  if (lines < 50) → STUB
  if (lines < 200) → INCOMPLETE
  if (lines >= 200) → HAS_COVERAGE
}

// Step 3: Identify gaps
missing = criticalPaths.filter(p => !hasTest(p))
```

### Phase 2: Priority Assessment

```
CRITICAL (write first)
├─ Authentication flow
├─ API auth + RLS enforcement
├─ Email processing
├─ Content generation
├─ Campaign execution
└─ Database operations

IMPORTANT (write next)
├─ UI rendering
├─ Form submission
├─ Navigation
├─ Error handling
└─ Edge cases

NICE-TO-HAVE (write if time)
├─ Performance
├─ Accessibility
└─ Analytics
```

### Phase 3: Test Writing

```
For each critical path:

1. UNDERSTAND THE FLOW
   - What does this feature do?
   - What are inputs/outputs?
   - What can go wrong?

2. WRITE TEST CASES
   - Happy path (normal operation)
   - Sad paths (errors, edge cases)
   - Boundary conditions

3. IMPLEMENT TESTS
   - Use appropriate testing library
   - Make assertions clear
   - Avoid mocking unless necessary

4. RUN & VERIFY
   - Test runs without errors
   - Breaks when code breaks
   - Clear failure messages
```

## Test Writing Guidelines

### Unit Tests (for functions/logic)

```typescript
describe('contactScoringEngine', () => {
  // GOOD: Tests specific behavior
  it('calculates score of 85 for high engagement contact', () => {
    const contact = {
      emailOpenRate: 0.8,
      emailClickRate: 0.6,
      sentiment: 'positive'
    };
    const score = scoreContact(contact);
    expect(score).toBe(85);
  });

  // BAD: Doesn't assert anything meaningful
  it('works', () => {
    scoreContact({...});
  });

  // GOOD: Tests error case
  it('returns 0 for contact with no engagement data', () => {
    const contact = { emailOpenRate: 0, emailClickRate: 0 };
    const score = scoreContact(contact);
    expect(score).toBe(0);
  });
});
```

### Integration Tests (for API routes + database)

```typescript
describe('POST /api/contacts', () => {
  // GOOD: Tests full flow with database
  it('creates contact and returns assigned ID', async () => {
    const response = await fetch('/api/contacts', {
      method: 'POST',
      headers: { Authorization: 'Bearer token' },
      body: JSON.stringify({
        email: '[email protected]',
        name: 'Test User'
      })
    });

    expect(response.status).toBe(201);
    const data = await response.json();
    expect(data.id).toBeDefined();

    // Verify it was actually saved
    const saved = await db.contacts.findById(data.id);
    expect(saved.email).toBe('[email protected]');
  });

  // GOOD: Tests authorization
  it('rejects request without valid auth token', async () => {
    const response = await fetch('/api/contacts', {
      method: 'POST',
      body: JSON.stringify({ email: '[email protected]' })
    });
    expect(response.status).toBe(401);
  });
});
```

### Component Tests (for React)

```typescript
describe('HotLeadsPanel', () => {
  // GOOD: Tests rendering and interaction
  it('displays hot leads and allows filtering', async () => {
    const { getByText, getByRole } = render(
      <HotLeadsPanel leads={mockLeads} />
    );

    expect(getByText('Hot Leads')).toBeInTheDocument();

    const filterBtn = getByRole('button', { name: /filter/i });
    fireEvent.click(filterBtn);

    expect(getByText('Filter options')).toBeInTheDocument();
  });

  // BAD: Just checks it renders without error
  it('renders', () => {
    render(<HotLeadsPanel leads={mockLeads} />);
  });
});
```

## Test Coverage Targets

```
API Routes
├─ Auth routes: 100% (critical security)
├─ CRUD operations: 95% (core functionality)
├─ Integration routes: 80% (complex flows)
└─ Utility routes: 70% (less critical)

Services
├─ Email service: 100% (revenue critical)
├─ Agent logic: 95% (core feature)
├─ Database queries: 90% (data integrity)
└─ Utilities: 70%

Components
├─ Critical path components: 90%
├─ UI components: 70%
└─ Utilities: 50%

Overall: Target 75%+ real coverage
```

## Running Tests

```bash
# Run all tests
npm test

# Run specific suite
npm test -- auth

# Run with coverage report
npm run test:coverage

# Watch mode for development
npm test -- --watch

# Generate coverage report
npm run test:coverage -- --reporter=html
```

## Dealing with Untestable Code

**If something is hard to test, that's a design problem.**

Red flags:
- Needs to mock 5+ dependencies
- Tests require heavy fixtures
- Can't test without hitting database
- State is global or hidden

Solutions:
1. Refactor for testability
2. Extract logic to pure functions
3. Separate concerns (data access vs logic)
4. Use dependency injection

## Test Maintenance

```
Monthly tasks:
├─ Update tests when features change
├─ Remove obsolete tests
├─ Review test performance (slow tests?)
├─ Check coverage hasn't dropped
└─ Refactor duplicated test code
```

## Quality Metrics

Track these:
- Lines of actual test code (growing)
- Real coverage % (not inflated by stubs)
- Test execution time (should stay <5min)
- Test flakiness (0 flaky tests)
- Bugs caught before production (trending up)

## Success Criteria

✅ All critical paths have real tests
✅ Tests are fast (<5 seconds)
✅ Tests catch bugs (coverage > 75%)
✅ No empty test files
✅ All tests pass on main branch
✅ Coverage trend is increasing

## Anti-Patterns (What We Stop)

❌ Empty test files that "count" toward coverage
❌ Stub tests with no assertions
❌ Mocking the thing you're testing
❌ Tests that pass whether code works or not
❌ Copy-paste tests (unmaintainable)
❌ One giant test file (hard to find issues)
❌ Writing tests after code (finds nothing)

---

**Key Mantra**:
> "An empty test file is admitting we don't know if it works.
> Real tests are how we earn the right to claim features are done."