@WebMvcTest for controller testing in Spring Boot - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What does @WebMvcTest load in the Spring context?

When you use @WebMvcTest on a controller class, which parts of the Spring application context are loaded for the test?

A No Spring context is loaded; it runs the controller in isolation without Spring support.

B Only the web layer components like controllers, filters, and related MVC components are loaded.

C Only the repository layer is loaded to test database interactions.

D The entire application context including services, repositories, and controllers is loaded.

💡 Hint

Think about what is needed to test just the web layer without starting the full app.

@WebMvcTest loads only the web layer components such as controllers and MVC infrastructure. It does not load services or repositories, so tests run faster and focus on controller behavior.

❓ state_output

intermediate

What is the HTTP status returned by this @WebMvcTest controller test?

Given this controller and test, what HTTP status code will the test receive?

Spring Boot

import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.junit.jupiter.api.Test;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

@WebMvcTest(HelloController.class)
class HelloControllerTest {
    @Autowired
    private MockMvc mockMvc;

    @Test
    void testHello() throws Exception {
        mockMvc.perform(get("/hello"))
               .andExpect(status().isOk());
    }
}

@RestController
class HelloController {
    @GetMapping("/hello")
    public String sayHello() {
        return "Hello!";
    }
}

A 404 Not Found

B 500 Internal Server Error

C 200 OK

D 302 Found (Redirect)

💡 Hint

The controller has a GET mapping for /hello that returns a string.

The @GetMapping("/hello") method returns a string and is reachable. The test expects status().isOk() which means HTTP 200. So the test will pass with status 200 OK.

📝 Syntax

advanced

Which @WebMvcTest annotation usage is correct for testing multiple controllers?

You want to test two controllers, UserController and OrderController, using @WebMvcTest. Which annotation usage is correct?

A @WebMvcTest({UserController.class, OrderController.class})

B @WebMvcTest(UserController.class, OrderController.class)

C @WebMvcTest(controllers = UserController.class, OrderController.class)

D @WebMvcTest(controllers = {UserController.class, OrderController.class})

💡 Hint

Check the syntax for specifying multiple controllers in the annotation attribute.

The controllers attribute expects an array of classes. The correct syntax uses curly braces {} to list multiple controllers.

🔧 Debug

advanced

Why does this @WebMvcTest fail with NoSuchBeanDefinitionException?

This test fails with NoSuchBeanDefinitionException for UserService. Why?

Spring Boot

import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.mock.mockito.MockBean;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.junit.jupiter.api.Test;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

@WebMvcTest(UserController.class)
class UserControllerTest {
    @Autowired
    private MockMvc mockMvc;

    @Test
    void testUser() throws Exception {
        mockMvc.perform(get("/user"))
               .andExpect(status().isOk());
    }
}

@RestController
class UserController {
    private final UserService userService;

    public UserController(UserService userService) {
        this.userService = userService;
    }

    @GetMapping("/user")
    public String getUser() {
        return userService.getName();
    }
}

interface UserService {
    String getName();
}

A The UserService bean is not found because @WebMvcTest does not load service beans unless mocked.

B UserService is an interface and cannot be mocked with @MockBean.

C The test forgot to add @MockBean for UserService, so Spring cannot inject it.

D The controller constructor is missing @Autowired, so injection fails.

💡 Hint

Think about what beans @WebMvcTest loads and how to provide dependencies.

@WebMvcTest loads only web layer beans. Service beans like UserService are not loaded unless you mock them with @MockBean. Without mocking, Spring cannot find UserService and throws NoSuchBeanDefinitionException.

🧠 Conceptual

expert

What is the main advantage of using @WebMvcTest over @SpringBootTest for controller tests?

Why would a developer choose @WebMvcTest instead of @SpringBootTest when testing controllers?

A @WebMvcTest loads only the web layer, making tests faster and more focused on controller logic.

B @WebMvcTest automatically mocks all dependencies, so no manual mocking is needed.

C @WebMvcTest runs the full application context including database connections for integration testing.

D @WebMvcTest disables Spring Security, so tests do not require authentication setup.

💡 Hint

Consider test speed and scope of loaded beans.

@WebMvcTest loads only the web layer components, which makes tests faster and focused on controller behavior. @SpringBootTest loads the full application context, which is slower and used for integration tests.