`@WebMvcTest` vs `@SpringBootTest` — when to use which?

Deep dive

These two annotations trade realism for speed.

`@WebMvcTest`

• Loads a **slice** of the context: MVC infrastructure + selected controller(s).
• Great for testing routing, validation, serialization, status codes, and error mapping.
• Typically uses `MockMvc` and mocks service dependencies (`@MockBean`).

`@SpringBootTest`

• Boots the **full** application context.
• Best for integration tests across layers (security, persistence, messaging).
• Often paired with Testcontainers to run real dependencies.

Practical guidance

• Use `@WebMvcTest` for controller-focused tests.
• Use `@SpringBootTest` for end-to-end integration scenarios.
• Consider other test slices: `@DataJpaTest`, `@JsonTest`, `@WebFluxTest`.

Common pitfalls

• Using `@SpringBootTest` everywhere (slow suite, brittle tests).
• Over-mocking in `@WebMvcTest` and missing real serialization/security issues.
• Not importing/configuring security for slice tests (or disabling filters without realizing the coverage gap).