spring-test-pyramidlisted

## Purpose Test Spring Boot applications at the right level — fast unit tests for logic, slower integration tests for data access. ## Checklist - **Unit tests (JUnit + Mockito)**: test service-layer logic in isolation. Mock repository and external dependencies. Fast — run in milliseconds. - **Repository integration tests (`@DataJpaTest`)**: test custom queries, entity mappings, and constraint enforcement against a real or embedded database. - **Controller slice tests (`@WebMvcTest`)**: test request mapping, validation, and response serialization. Mock service layer. - **Full context tests (`@SpringBootTest`)**: use sparingly for critical end-to-end paths only. Slow — don't use for every test. - **Coverage**: every service method has a unit test. Every custom repository query has an integration test. Every controller endpoint has a slice test for error paths. ## Expected output A test suite where unit tests cover business logic, integration tests cover data access, and full-context tests cover only critical paths.