单元测试给出 NullPointerException

Posted 2023-02-27

【中文标题】单元测试给出 NullPointerException

【英文标题】：Unit test gives NullPointerException

【发布时间】：2021-01-07 05:36:27

【问题描述】：

我正在尝试为 handler.sendRequest(request); 编写一个单元测试用例。功能。但是，它返回空指针异常。 当我在单元测试中打印请求对象时，它返回 null。但是，我已经初始化了请求对象，不确定它为什么给出空指针异常。数据对象有问题吗？我错过了什么吗？有人可以帮忙吗？谢谢！

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;
    

它在handler.sendRequest(request); 内的getAuthHandler().requestToken(); 函数中给我一个错误

下面是堆栈跟踪：

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)

【问题讨论】：

您创建模拟，创建处理程序的新实例，但不要将模拟注入处理程序。

@M.Deinum 感谢您的回复。您能否帮助我了解如何将模拟注入处理程序帮助或我该怎么做？

使用@InjectMocks 后还是同样的错误。请协助我修复缺少的内容。

请将堆栈跟踪添加到您的问题中。

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

【参考方案1】：

您应该使用@InjectMocks 将模拟注入ServicesHandler，有关更多信息，请参阅文档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);
   

【讨论】：

感谢您的帮助！我试过@Injectmocks 但是，它仍然给我一个空指针异常。如果我遗漏了什么，你能帮帮我吗？

我是否遗漏了 requestToken 的某些内容？

你忘了使用跑步者，比如@RunWith(MockitoJUnitRunner.class)

@Milgo 我添加了@RunWith(MockitoJunitRunner.class) 仍然是同样的错误。

@Milgo 只是想知道。加跑步者需要什么？