Choosing the right test double in JUnit - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a mock object using Mockito.

JUnit

MyService service = Mockito.[1](MyService.class);

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

Aspy

Bmock

Cverify

Dwhen

Attempts:

3 left

💡 Hint

Common Mistakes

Using spy instead of mock when a full mock is needed.

Using verify to create objects, which is for checking calls.

The mock method creates a mock object for the given class.

2fill in blank

medium

Complete the code to verify that a method was called once on a mock.

JUnit

Mockito.[1](mockObject).someMethod();

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

Aspy

Bmock

Cverify

Dwhen

Attempts:

3 left

💡 Hint

Common Mistakes

Using mock() instead of verify() for checking calls.

Confusing spy with verify.

The verify method checks if a method was called on a mock.

3fill in blank

hard

Fix the error in the code to stub a method call on a spy object.

JUnit

Mockito.[1](spyObject.someMethod()).thenReturn("value");

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

Amock

Bspy

Cverify

Dwhen

Attempts:

3 left

💡 Hint

Common Mistakes

Using verify instead of when for stubbing.

Using mock instead of when for stubbing.

The when method is used to stub method calls on mocks or spies.

4fill in blank

hard

Fill both blanks to create a spy and stub a method to return a value.

JUnit

MyService spyService = Mockito.[1](new MyService());
Mockito.[2](spyService.someMethod()).thenReturn("Hello");

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

Aspy

Bmock

Cwhen

Dverify

Attempts:

3 left

💡 Hint

Common Mistakes

Using mock instead of spy to wrap a real object.

Using verify instead of when for stubbing.

First, create a spy with spy(). Then stub a method call with when().

5fill in blank

hard

Fill all three blanks to mock a repository, stub a method, and verify the call.

JUnit

Repository repo = Mockito.[1](Repository.class);
Mockito.[2](repo.findById(1)).thenReturn(Optional.of(new Item()));
Mockito.[3](repo).findById(1);

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

Amock

Bwhen

Cverify

Dspy

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing spy and mock incorrectly.

Using verify before when.

Create a mock with mock(), stub a method with when(), and verify the call with verify().