322-frameworks-spring-boot-testing-integration-tests

# Spring Boot Integration Testing Apply Spring Boot integration testing guidelines for Spring Boot 4.0.x. **What is covered in this Skill?** - Integration test scope and purpose (verify wiring and contracts, not unit-test duplication) - Testcontainers with @ServiceConnection for zero-config wiring (preferred) - @DynamicPropertySource as fallback for containers without built-in service connection support - Static @Container instances shared across test methods for performance - MockMvcTester for fluent AssertJ-based HTTP assertions (Spring Boot 4.0.x) - TestRestTemplate for full HTTP stack testing - @DataJdbcTest / @DataJpaTest persistence slices (load only persistence layer, start faster) - Data isolation: each test owns its scenario; no shared mutable state or ordering assumptions - @MockitoBean for mock registration (Spring Boot 4.0.x — @MockBean removed) - Resource lifecycle: Testcontainers JUnit integration for teardown; *IT / integration test separation **Scope:** Apply recommendations based on the reference rules and good/bad code examples. ## Constraints Before applying any integration test changes, ensure the project compiles. If compilation fails, stop immediately. After applying improvements, run full verification. - **MANDATORY**: Run `./mvnw compile` or `mvn compile` before applying any change - **SAFETY**: If compilation fails, stop immediately - **VERIFY**: Run `./mvnw clean verify` or `mvn clean verify` after applying improvements - **BEFORE APPLYING**: ...