CODEWITHSUNDEEP
javaspring-bootjunitmockito
prometheusnoob
prometheusnoob

Reputation: 167

Mockito is not mocking out a member variable method return value

I have the following class that contains a member variable, but Mockito can't seem to mock the member variable's methods. Below is my System Under Test:

public class MessageConsumer {

    private ConsumerResponse consumerResponse;
    private NotificationConsumer notificationConsumer;

    @Scheduled(cron = "${com.example.value}")
    public void fetch() {
        consumerResponse = notificationConsumer.fetchWithReturnConsumerResponse(); //no exception thrown on this line at all -- but could this be the cause of the problem in the test?
        System.out.println("consumerResponse's responseCode: " + consumerResponse.getResponseCode()); // NullPointerException thrown here
    }

    public ConsumerResponse setConsumerResponse(ConsumerResponse consumerResponse) {
        this.consumerResponse = consumerResponse;
    }

    public ConsumerResponse getConsumerResponse() {
        return consumerResponse;
    }
}

And the following is the relevant JUnit test for the class: 

@SpringBootTest
@RunWith(MockitoJUnitRunner.class)
public class MessageConsumerTest {

    @Mock
    private ConsumerResponse consumerResponse;

    @InjectMocks
    private MessageConsumer messageConsumer;

    @Before
    public void setup() {
        MockitoAnnotations.initMocks(this);
    }

    //Failing unit test
    @Test
    public void getResponseCodeShouldReturn200() {
        Mockito.when(consumerResponse.getResponseCode()).thenReturn("200");
        messageConsumer.fetch()
    }

}

As you can see, I've mocked the ConsumerResponse consumerResponse variable to return "200" when the consumerResponse.getResponseCode() method gets invoked. Instead, I'm getting a NullPointerException.

I'm pretty sure I mocked the member variable correctly and initialized it appropriately (initMocks). I've spent days trying to figure this out. Where am I going wrong?

Upvotes: 0

Views: 1455

Answers (1)

rieckpil
rieckpil

Reputation: 12051

As NotificationConsumer is also an external dependency for this class, you have to also mock this class as otherwise consumerResponse = notificationConsumer.fetchWithReturnConsumerResponse(); will result into null within your test as you didn't mock the NotificationConsumer. In addition I would suggest not to use @SpringBootTest within this unit test as this annotation will boot the whole Spring context. The following snippet should help you:

@RunWith(MockitoJUnitRunner.class)
public class MessageConsumerTest {

    @Mock
    private ConsumerResponse consumerResponse;

    @Mock
    private NotificationConsumer notificationConsumer;

    @InjectMocks
    private MessageConsumer messageConsumer;

    @Before
    public void setup() {
        MockitoAnnotations.initMocks(this);
    }

    @Test
    public void getResponseCodeShouldReturn200() {
        Mockito.when(notificationConsumer.fetchWithReturnConsumerResponse()).thenReturn(consumerResponse);
        Mockito.when(consumerResponse.getResponseCode()).thenReturn("200");
        messageConsumer.fetch();
    }

}

Upvotes: 3

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