单元测试给出 NullPointerException

Question

I'm trying to write a unit test case for the handler.sendRequest(request); function. However, it returns the null pointer exception. When I print the request object in the unit test it returns null. However, I have initialized the request object not sure why it is giving null pointer exception. Is something wrong with the Data object? Have I missed something? Can someone please help? Thanks!

public class ServicesHandlerTest {

    @Mock
    private RestTemplate restTemplate;

    @Mock
    private ObjectMapper mapper;

    @Mock
    private AuthHandler AuthHandler;

    @InjectMocks
    ServicesHandler handler;

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

    @After
    public void tearDown() throws Exception {
    }

    @Test
    public void testSuccess() throws Exception {
        Data data = new Data();
        data.setRequestId(UUID.randomUUID().toString());  
        data.setRequestedQuantity(10);

        Request request = new Request();
        request.setData(data );

        System.out.println("request = " + request);
        ServicesHandler handler = new ServicesHandler();
        Mockito.when(AuthHandler.requestToken()).thenReturn("randomString");
Mockito.when(msAuthHandler.createAuthorizationBearerHttpHeaders("randomString")).thenReturn(any());
        Mockito.when(restTemplate.postForEntity(anyString(), any(), eq(String.class))).thenReturn(new ResponseEntity<String>(HttpStatus.OK));
        handler.sendRequest(request);
    }

 @Component
 public class ServicesHandler extends AbstractHandler {

    @Value("${api.host}")
    private String msApiHost;

    @Value("${base.path}")
    private String BasePath;

    @Autowired
    private AuthHandler authHandler;

    public AuthHandler getAuthHandler() {
        return authHandler;
    }



   public ResponseEntity<String> sendRequest(Request pr) throws Exception {
    
   ResponseEntity<String> response = null;

        try {
            String requestToken = getAuthHandler().requestToken();

            HttpHeaders headers = getAuthHandler().createAuthorizationBearerHttpHeaders(requestToken);
            
            String apiUrl = ApiHost + BasePath;

            RestTemplate restTemplate = new RestTemplate();
            MappingJackson2HttpMessageConverter mappingJackson2HttpMessageConverter = new MappingJackson2HttpMessageConverter();
            ObjectMapper objectMapper = new ObjectMapper();
            objectMapper.setSerializationInclusion(Include.NON_NULL);
            mappingJackson2HttpMessageConverter.setObjectMapper(objectMapper);
            restTemplate.getMessageConverters().add(mappingJackson2HttpMessageConverter);

        HttpEntity<Request> request = new HttpEntity<Request>(pr, headers);
            response = restTemplate.postForEntity(apiUrl, request, String.class);
        } catch (HttpStatusCodeException e) {
            logger.error("Error when sending for provisioning " + e.getResponseBodyAsString(), e);
            return ResponseEntity.status(e.getStatusCode()).body(e.getResponseBodyAsString());
        } catch (Exception e) {
            throw e;
        }

        return response;
   }
 }

public class Data {
    private String requestId;
    private Integer requestedQuantity;

    public String getRequestId() {
        return requestId;
    }

    public void setRequestId(String requestId) {
        this.requestId = requestId;
    }

    public Integer getRequestedQuantity() {
        return requestedQuantity;
    }

    public void setRequestedQuantity(Integer requestedQuantity) {
        this.requestedQuantity = requestedQuantity;
    }
}

It gives me an error in getAuthHandler().requestToken(); function inside handler.sendRequest(request);

Below is the stacktrace:

java.lang.NullPointerException at com.xyz.abc.sendRequest(ServicesHandler.java:443) at com.xyz.abc.ServicesHandlerTest.testSuccess(ServicesHandlerTest.java:150) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498)

Answer 1

You should inject the mocks into ServicesHandler using @InjectMocks , see the docs for more information MockitoAnnotations.initMocks

public class ServicesHandlerTest {

    @InjectMocks
    private ServicesHandler;

    @Mock
    private RestTemplate restTemplate;

    @Mock
    private ObjectMapper mapper;

    @Mock
    private AuthHandler AuthHandler;

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

    @After
    public void tearDown() throws Exception {
    }

    @Test
    public void testSuccess() throws Exception {
         Data data = new Data();
         data.setRequestId(UUID.randomUUID().toString());  
         data.setRequestedQuantity(10);

         Request request = new Request();
         request.setData(data );

         System.out.println("request = " + request);
    
    
   Mockito.when(AuthHandler.requestToken()).thenReturn("randomString");
    Mockito.when(restTemplate.postForEntity(anyString(), any(), eq(String.class))).thenReturn(new ResponseEntity<String>(HttpStatus.OK));
    handler.sendRequest(request);
   }
}