@Mock annotation in JUnit - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a mock object using the @Mock annotation.

JUnit

public class UserServiceTest {
    @[1]
    private UserRepository userRepository;
}

Drag options to blanks, or click blank then click option'

AMock

BInjectMocks

CAutowired

DTest

Attempts:

3 left

💡 Hint

Common Mistakes

Using @InjectMocks instead of @Mock

Forgetting the '@' symbol

Using @Test annotation here

The @Mock annotation is used to create a mock object for the UserRepository in the test class.

2fill in blank

medium

Complete the code to initialize mocks before running tests.

JUnit

@BeforeEach
public void setup() {
    Mockito[1](this);
}

Drag options to blanks, or click blank then click option'

AcreateMocks

BinitMocks

CstartMocks

DopenMocks

Attempts:

3 left

💡 Hint

Common Mistakes

Using deprecated initMocks method

Misspelling the method name

Not calling any initialization method

Mockito.openMocks(this) initializes the mock objects annotated with @Mock before each test.

3fill in blank

hard

Fix the error in the test method to use the mock correctly.

JUnit

@Test
public void testFindUser() {
    when(userRepository.findById([1])).thenReturn(Optional.of(new User()));
    User user = userService.findUserById(1);
    assertNotNull(user);
}

Drag options to blanks, or click blank then click option'

A1

BanyInt()

C"1"

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using a raw value '1' causing mismatch if argument differs

Using a string instead of integer

Passing null as argument

Using anyInt() matcher allows the mock to respond to any integer argument, avoiding strict matching errors.

4fill in blank

hard

Fill both blanks to correctly verify the mock interaction.

JUnit

@Test
public void testSaveUser() {
    User user = new User();
    userService.saveUser(user);
    verify(userRepository, [1]).save([2]);
}

Drag options to blanks, or click blank then click option'

Atimes(1)

Bany()

Cnever()

Deq(user)

Attempts:

3 left

💡 Hint

Common Mistakes

Using never() instead of times(1)

Using any() instead of eq(user)

Omitting verify call

verify(userRepository, times(1)).save(eq(user)) checks that save was called once with the exact user object.

5fill in blank

hard

Fill all three blanks to create a mock and inject it into the service under test.

JUnit

public class OrderServiceTest {
    @[1]
    private OrderRepository orderRepository;

    @[2]
    private OrderService orderService;

    @BeforeEach
    public void init() {
        Mockito.[3](this);
    }
}

Drag options to blanks, or click blank then click option'

AMock

BInjectMocks

CopenMocks

DBefore

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing @Mock and @InjectMocks annotations

Using deprecated initMocks method

Forgetting to initialize mocks

Use @Mock for the repository, @InjectMocks for the service, and Mockito.openMocks(this) to initialize mocks.