Testing Guidelines

Unit Tests

• Test one thing per test
• Use descriptive test names: test_user_creation_fails_with_invalid_email
• Mock external dependencies
• Keep tests fast and isolated

Integration Tests

• Test API endpoints with realistic data
• Verify database state changes
• Clean up test data after each test
• Use test fixtures for common scenarios

Running Tests

# Run all tests
npm test

# Run unit tests only
npm test:unit

# Run integration tests (requires database)
npm test:integration

# Run tests with coverage
npm test:coverage

Test Structure

tests/
├── unit/           # Fast, isolated unit tests
├── integration/    # Tests requiring external services
├── fixtures/       # Shared test data
└── helpers/        # Test utilities

Best Practices

1. Arrange-Act-Assert: Structure tests clearly
2. One assertion per test: When possible, test one behavior
3. Descriptive names: Test names should describe the scenario
4. No test interdependence: Tests should run in any order
5. Clean state: Each test starts with a known state

Coverage Goals

• Aim for 80%+ line coverage
• Focus on critical paths first
• Don’t sacrifice test quality for coverage numbers