@WebMvcTest vs @SpringBootTest for Controllers

Direct Answer

@WebMvcTest creates a focused MVC test slice and auto-configures MockMvc without starting a server. @SpringBootTest creates a broader Boot ApplicationContext and can start a server for RANDOM_PORT or DEFINED_PORT. Neither has a fixed startup time, and neither automatically proves every external integration; choose the smallest boundary that includes the behavior under test.

Code Example

// MVC slice: service behavior is controlled by a test double.
@WebMvcTest(OrderController.class)
class OrderControllerSliceTest {
    @Autowired MockMvc mockMvc;
    @MockitoBean OrderService orderService;

    @Test
    void returnsOrder() throws Exception {
        when(orderService.findById(1L)).thenReturn(new Order(1L, "Laptop", 999.0));
        mockMvc.perform(get("/api/orders/1"))
               .andExpect(status().isOk())
               .andExpect(jsonPath("$.item").value("Laptop"));
    }
}

// Broader Boot context: only the boundaries configured for this test are real.
@SpringBootTest
@AutoConfigureMockMvc
class OrderControllerBootTest {
    @Autowired MockMvc mockMvc;

    @Test
    void acceptsCreateRequest() throws Exception {
        mockMvc.perform(post("/api/orders")
                 .contentType(MediaType.APPLICATION_JSON)
                 .content("{\"item\":\"Mouse\",\"price\":25.0}"))
               .andExpect(status().isCreated());
    }
}

The second test proves persistence only if its profile and configuration provide the intended database and the assertion checks stored state. @SpringBootTest alone does not make every boundary real or make the test end to end.

Common Mistakes & Pitfalls

• Choosing by habit: Use the smallest boundary that contains the behavior, not one annotation for every controller test.
• Leaving slice collaborators absent: Provide them with @MockitoBean, older @MockBean, @Import, or test configuration.
• Assuming a broad context means no mocks: Selective bean overrides can be useful when one remote dependency is outside the test scope.
• Calling a test end-to-end without real boundaries: State which server, database, broker, or external system is actually present.