java-spring-boot-testing

Structure Spring Boot tests by separating unit tests with Mockito for service components, MockMvc for controller slices, and @SpringBootTest with Testcontainers for integration tests. This approach ensures fast feedback loops and deterministic end-to-end scenario validation.

The best way to test Spring Boot JPA repositories is using @DataJpaTest with TestEntityManager. This combination creates deterministic data states for your data-layer testing without requiring a fully running application context.

Yes, you can use WebTestClient for Spring Boot controller testing. It supports testing web layer patterns alongside MockMvc slice tests and standalone tests, allowing you to verify MVC patterns and reactive web endpoints effectively.

Spring Boot testing supports contract testing through Spring Cloud Contract. It enables end-to-end scenarios alongside integration tests using @SpringBootTest and Testcontainers to verify interactions across varying project sizes.

Use Testcontainers for Spring Boot integration testing to verify end-to-end scenarios against real database instances. Unlike mocked databases, Testcontainers ensures reproducible test data and validates actual JPA data-layer behavior deterministically.