Comprehensive Testing Skill

<!-- Generated by tools/exporter.py from skills/test_skill.md -->
<!-- Do not edit manually. Re-run: python tools/exporter.py -->

# Comprehensive Testing Skill

## Purpose

Generate and execute comprehensive tests across backend, frontend, and integration layers with coverage metrics.

## Input

- Completed code from all tasks (backend, frontend)
- Task specifications (acceptance criteria)
- Coverage targets: >= 95% overall, >= 90% per layer

## Output

- Backend tests: `tests/unit/*.test.py`, `tests/integration/*.integration.py`
- Frontend tests: `tests/components/*.test.tsx`
- E2E tests: `tests/e2e/*.e2e.ts`
- Coverage reports: `coverage.html`, `coverage.json`

## Process

### Backend Testing (pytest)

1. Generate unit tests for models, services, routes
2. Create mocks for external dependencies
3. Test happy paths and error cases
4. Achieve >= 95% coverage

```python
# tests/unit/test_user_service.py
import pytest
from src.services.user_service import UserService
from src.models.user import User

@pytest.fixture
def service():
    return UserService()

def test_create_user_success(service):
    """Test successful user creation."""
    result = service.create_user("test@example.com", "hashedpwd")
    assert result.email == "test@example.com"
    assert result.id is not None

def test_create_duplicate_user_raises_error(service):
    """Test that duplicate user creation raises error."""
    service.create_user("test@example.com", "pwd")
    with pytest.raises(ValueError):
        service.create_user("test@example.com", "pwd")
```

### Frontend Testing (Jest + Playwright)

1. Generate component tests for each component
2. Create Playwright E2E tests for user flows
3. Test form validation and error handling
4. Achieve >= 85% component coverage

```typescript
// tests/components/LoginForm.test.tsx
import { render, screen, userEvent } from '@testing-library/react';
import { LoginForm } from '../components/LoginForm';

test('submits form with valid credentials', async () => {
  const handleSuccess = jest.fn();
  render(<LoginForm onSuccess={handleSuccess} />);
  
  const emailInput = screen.getByLabelText(/email/i);
  const passwordInput = screen.getByLabelText(/password/i);
  const submitButton = screen.getByRole('button', { name: /login/i });
  
  await userEvent.type(emailInput, 'test@example.com');
  await userEvent.type(passwordInput, 'password123');
  await userEvent.click(submitButton);
  
  expect(handleSuccess).toHaveBeenCalled();
});
```

### Coverage Reporting

1. Generate coverage reports for both layers
2. Fail if coverage < targets
3. Create HTML report

## Validation

- [ ] All unit tests pass
- [ ] All integration tests pass
- [ ] All E2E tests pass
- [ ] Coverage >= 95% (backend)
- [ ] Coverage >= 85% (frontend)
- [ ] No flaky tests
- [ ] Test execution time < 60 seconds

## Success Criteria

- All tests green
- Coverage reports generated
- Overall coverage >= 95%
- No hardcoded test data leaking into reports
- Performance metrics tracked

## Execution Commands

```bash
# Backend tests
pytest tests/ -v --cov=src --cov-report=html --cov-report=json

# Frontend tests
npm test -- --coverage --watchAll=false

# E2E tests
playwright test
```