@MockBean for Spring mocking in JUnit - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a mock bean for the UserService in a Spring test.

JUnit

@SpringBootTest
public class UserServiceTest {

    @[1]
    private UserService userService;

    @Test
    public void testUser() {
        // test logic here
    }
}

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AAutowired

BInjectMocks

CMockBean

DMock

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Mock instead of @MockBean in Spring Boot tests.

Forgetting to annotate the test class with @SpringBootTest.

The @MockBean annotation creates a mock of the UserService and adds it to the Spring context for testing.

2fill in blank

medium

Complete the code to verify that the mocked UserRepository is called once in the test.

JUnit

@MockBean
private UserRepository userRepository;

@Test
public void testFindUser() {
    userService.findUserById(1L);
    verify([1]).findById(1L);
}

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AuserRepository

BmockUserRepository

Crepository

DuserService

Attempts:

3 left

💡 Hint

Common Mistakes

Verifying the service instead of the repository mock.

Using a variable name not declared in the test.

We verify the mock userRepository to check if its findById method was called with argument 1L.

3fill in blank

hard

Fix the error in the test setup by completing the annotation to mock the EmailService bean.

JUnit

@SpringBootTest
public class NotificationTest {

    @[1]
    private EmailService emailService;

    @Test
    public void sendEmailTest() {
        when(emailService.sendEmail(anyString())).thenReturn(true);
        // test logic
    }
}

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AMock

BMockBean

CInjectMocks

DAutowired

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Mock instead of @MockBean causing Spring context errors.

Not annotating the test class with @SpringBootTest.

Use @MockBean to mock EmailService in Spring Boot tests so Spring context uses the mock.

4fill in blank

hard

Fill both blanks to mock the PaymentService and inject the mock into OrderService.

JUnit

@SpringBootTest
public class OrderServiceTest {

    @[1]
    private PaymentService paymentService;

    @Autowired
    private OrderService orderService;

    @BeforeEach
    public void setup() {
        MockitoAnnotations.[2](this);
    }

    @Test
    public void testPayment() {
        when(paymentService.processPayment(anyDouble())).thenReturn(true);
        // test logic
    }
}

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AMockBean

BInjectMocks

CopenMocks

DinitMocks

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Mock instead of @MockBean in Spring tests.

Using deprecated initMocks instead of openMocks.

Use @MockBean to mock PaymentService in Spring context. Use MockitoAnnotations.openMocks(this) to initialize mocks.

5fill in blank

hard

Fill all three blanks to create a mock bean for InventoryService, inject it, and verify a method call.

JUnit

@SpringBootTest
public class InventoryTest {

    @[1]
    private InventoryService inventoryService;

    @Autowired
    private InventoryController inventoryController;

    @Test
    public void testInventoryUpdate() {
        inventoryController.updateStock(5);
        verify([2]).updateStock([3]);
    }
}

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AMockBean

BinventoryService

C5

DMock

Attempts:

3 left

💡 Hint

Common Mistakes

Using @Mock instead of @MockBean causing Spring context issues.

Verifying the controller instead of the mock service.

Using wrong argument in verify call.

Use @MockBean to mock InventoryService. Verify the mock inventoryService received updateStock call with argument 5.