Database Testing

DB Test with Testcontainers

@SpringBootTest
class DatabaseTest {

    @Container
    static PostgreSQLContainer<?> db = new PostgreSQLContainer<>("postgres:15");

    @Autowired private UserRepository userRepository;

    @Test
    @Transactional
    void shouldPersistUser() {
        User user = new User("alice", "alice@example.com");
        userRepository.save(user);

        Optional<User> found = userRepository.findByUsername("alice");
        assertThat(found).isPresent();
        assertThat(found.get().getEmail()).isEqualTo("alice@example.com");
    }
}

Testing Pyramid

     /  E2E  \
    /----------\
   / Integration \
  /----------------\
 /      Unit        \
/--------------------

Test Types

• Unit: Individual components
• Integration: Component interactions
• E2E: Full user workflows
• Performance: Load/stress testing

Best Practices

• Write tests first (TDD)
• Aim for 80% coverage
• Test edge cases
• Keep tests fast and isolated

Key Points

• Understanding Database Testing is essential for production systems
• Always consider scalability and maintainability
• Test thoroughly before deploying to production
• Monitor performance and set up alerting

Common Patterns

1. Validation: Always validate input at the boundary
2. Error Handling: Use structured error responses
3. Logging: Log key events for debugging
4. Testing: Unit, integration, and load tests
5. Documentation: Keep docs updated with code changes