unit-test-controller-layer

Use @WebMvcTest to load only the web layer and MockMvc to test controller behavior in isolation. This approach verifies request/response mappings, HTTP status codes, and serialization without spinning up services or database connections, enabling fast feedback on controller logic.

Yes. MockMvc lets you verify parameter binding, validation constraints, and validation error responses without the full Spring stack. Combine it with Mockito-mocked services to test how controllers handle invalid input and constraint violations.

Use @WebMvcTest with @ControllerAdvice to validate exception-to-response mappings. MockMvc verifies that exceptions produce correct HTTP status codes and error response bodies, confirming your error handling strategy works as intended.

Set up a standalone MockMvc instance with @WebMvcTest, mock service dependencies using Mockito, and write parameterized or grouped tests for each HTTP verb. This isolated approach runs orders of magnitude faster than integration tests while covering request/response contracts.

Yes. MockMvc lets you validate content-type headers, JSON/XML serialization, and response body structure without hitting a real database or service. This catches mapping mismatches and serialization bugs early.

WebMvcTest loads only the web layer, skipping service initialization, database setup, and application startup. Tests run in milliseconds rather than seconds, providing rapid feedback on controller behavior while Mockito handles service dependencies.