java - 构造函数中模拟 bean 的 NullPointerException - 如何通过首先自定义构造函数来正确模拟模拟 Bean？

Question

我在 WebClient.Builder 实例的测试类中使用 @MockBean 注释，当我尝试设置 SSL 上下文时，它会导致 NullPointerException。

我不知道为什么当我没有尝试设置上下文并简单地调用 build() api 时没有看到错误，如下 v1 所示:

服务类 v1:

@Service
public class ABCD {

private static final Logger logger = LoggerFactory.getLogger(ABCD.class);

private String apiUrl;

private final WebClient webClient;
private final XYZRepository repository;

public ABCD(WebClient.Builder webClientBuilder,
                   XYZRepository repository, @Value("${api-root-url}") String apiUrl) {

    //------------------------
    this.webClient = webClientBuilder.build();
    //------------------------
    this.repository = repository;
    this.apiUrl = apiUrl;
    }
}

服务类 v2:

@Service
public class ABCD {

private static final Logger logger = LoggerFactory.getLogger(ABCD.class);

private String apiUrl;

private final WebClient webClient;
private final XYZRepository repository;

public ABCD(WebClient.Builder webClientBuilder,
                   XYZRepository repository, @Value("${api-root-url}") String apiUrl) throws SSLException {

    SslContext sslContext = SslContextBuilder
            .forClient()
            .trustManager(InsecureTrustManagerFactory.INSTANCE)
            .build();
    ClientHttpConnector httpConnector = new ReactorClientHttpConnector(options -> options.sslContext(sslContext));

    //------------------------
    this.webClient = webClientBuilder
            .clientConnector(httpConnector)
            .build();
    //------------------------
    this.repository = repository;
    this.apiUrl = apiUrl;
    }
}

测试类:

@RunWith(SpringRunner.class)
@WebFluxTest(ABCD.class)
public class ABCDTest {

    @MockBean
    XYZRepository repository;

    @MockBean
    WebClient.Builder webClientBuilder;

    @SpyBean
    ABCD ABCDService;


    WebClient webClient;

    @Value("${api-root-url}")
    String apiRootUrl;

    @Before
     public void setup() {
         this.objMapper = new ObjectMapper();
         this.mockWebServer = new MockWebServer();
         String baseUrl = this.mockWebServer.url("/").toString();
         this.webClient = WebClient.create(baseUrl);

         MockitoAnnotations.initMocks(this);
         ReflectionTestUtils.setField(ABCDService,
                 "apiRootUrl", API_ROOT_URL);
         ReflectionTestUtils.setField(ABCDService,
                 "webClient", this.webClient);
     }

    }

这里是 v2

this.webClient = webClientBuilder .clientConnector(httpConnector) .build();

在 build() 调用上导致 NPE。如何在不导致 NPE 的情况下模拟 Web 客户端？

我尝试在 setup() 方法中添加以下代码来模拟 clientConnector 方法的响应:

when(this.webClientBuilder.clientConnector(any()))
                .thenReturn(this.webClientBuilder);

所以，我很好奇可以在哪里添加这段代码来使用上面的模拟。

Answer 1

我认为 webClientBuilder 已作为模拟创建成功(它不是空的 - 是吗？)，但是您还没有告诉该模拟当 clientConnector< 时要做什么 方法被调用。因此，Mockito 的默认行为是返回 null - 因此，当您对该响应调用 build() 时，您的 NPE 就会返回。

因此，您需要 webClientBuilder 从 clientConnector 方法返回自身，并从 build 返回 webClient ()。通过添加以下行来完成此操作:

when(webClientBuilder.clientConnector(any(ClientHttpConnector.class))).thenReturn(webClientBuilder);
when(webClientBuilder.build()).thenReturn(webClient);