Which test annotation starts the FULL Spring application context, and which loads only the web layer?

@WebMvcTest starts the full context; @SpringBootTest loads the web layer
@SpringBootTest starts the full context; @WebMvcTest loads the web layer (Correct option)
Both annotations always load the whole application context
@DataJpaTest starts the full context of the application

@SpringBootTest is full; @WebMvcTest loads only controllers and web components (with MockMvc)

@SpringBootTest starts the whole application: slow but realistic (integration tests).

Test slices load only the part you are testing, so they are faster:

@WebMvcTest(UserController.class): only the web layer; you mock services and call endpoints with MockMvc.
@DataJpaTest: only JPA and repositories, with an in-memory database by default.

For pure unit tests of a service, skip Spring: use JUnit + Mockito.

Slices (@WebMvcTest, @DataJpaTest) are fast; @SpringBootTest is the full app.