mock instance is null after @Mock annotation

Question

I try to run this test:

    @Mock IRoutingObjHttpClient routingClientMock;     @Mock IRoutingResponseRepository routingResponseRepositoryMock;       @Test     public void testSendRoutingRequest() throws Exception {         CompleteRoutingResponse completeRoutingResponse = new CompleteRoutingResponse();         completeRoutingResponse.regression_latencyMillis = 500L;          Mockito.when(routingClientMock.sendRoutingRequest(any(RoutingRequest.class))).thenReturn(completeRoutingResponse);          RoutingObjHttpClientWithReRun routingObjHttpClientWithReRun = new RoutingObjHttpClientWithReRun                 (routingClientMock, routingResponseRepositoryMock);  ...     } 

but I get NullPointerException for:

Mockito.when(routingClientMock.

what am i missing?

Answer 1

When you want to use the @Mock annotation you should use the MockitoJUnitRunner

@RunWith(MockitoJUnitRunner.class) public class MockitoTest {      @Mock     private IRoutingObjHttpClient routingClientMock;      @Test     public void testSendRoutingRequest() throws Exception {         // ...     }  } 

See also this tutorial.

Answer 2

You have three options for activating the @Mock annotation: MockitoRule, MockitoJUnitRunner, MockitoAnnotations.initMocks(this). IMHO using the MockitoRule is the best one, because it lets you still choose another runner like e.g. Parameterized.

Use the MockitoRule

public class MockitoTest {    @Mock   private IRoutingObjHttpClient routingClientMock;    @Rule   public MockitoRule rule = MockitoJUnit.rule();    @Test   public void testSendRoutingRequest() throws Exception {     // ...   } } 

Use the MockitoJUnitRunner

@RunWith(MockitoJUnitRunner.class) public class MockitoTest {    @Mock   private IRoutingObjHttpClient routingClientMock;    @Test   public void testSendRoutingRequest() throws Exception {     // ...   } } 

Call MockitoAnnotations.initMocks(this) explicitly.

This can be done in qn @Before method, in your own runner or in an own rule.

public class MockitoTest {    @Mock   private IRoutingObjHttpClient routingClientMock;    @Before   public void createMocks() {     MockitoAnnotations.initMocks(this);   }    @Test   public void testSendRoutingRequest() throws Exception {     // ...   } }