java - 模拟 RxJava 异步 http 调用

Question

我在模拟进行一些 HTTP 调用的 RxJava 函数时遇到了一些麻烦。我正在使用 JUnit 和 Mockito。

//Customer.java extends ServiceManager
public Observable<String> getCustomerDetails(String uuidData){
    String api = "http://someapi.com/" + uuidData;
    return callHttps(api, getHeader(),
            "",
            HttpMethod.GET)
            .doOnError(failure -> logger.error("Error was raised while calling Profile Save of ORCH API:"
                    + failure.getMessage()))
            .doOnNext(httpClientResponse -> {
                logger.info("");
            })
            .concatMap(RxHelper::toObservable)
            .reduce(Buffer.buffer(), Buffer::appendBuffer)
            .map(buffer -> buffer.toString("UTF-8"))
            .map(entries -> entries);
}

private MultiMap getProfileHeader(){
    MultiMap headers = MultiMap.caseInsensitiveMultiMap();
    headers.add("Accept","application/json");
    return headers;
}


public class ServiceManager {
    @Inject
    @Named("httpsClient")
    private HttpClient httpsClient;

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

    public Observable<HttpClientResponse> callHttps(String url, MultiMap headers, String body, HttpMethod httpMethod) {
        return Observable.create(subscriber -> {
            HttpClientRequest httpClientRequest = httpsClient.requestAbs(httpMethod, url);
            httpClientRequest.exceptionHandler(event -> {
               logger.error("Exception was raised :" + event.getMessage());
            });
            httpClientRequest.headers().addAll(headers);
            RxHelper
                    .toObservable(httpClientRequest)
                    .subscribe(subscriber);

            httpClientRequest.end(body);
        });
    }
}

如何模拟 callHttps 函数，以便它返回一个 HttpClientRequest 模拟响应。对我来说，另一种方法是使用 WireMock，但我想通过模拟上述函数来找到一种方法。

Answer 1

假设 Customer 不必是最终的，您可以使用 Self-Shunt Pattern 。基本上，在这种模式中，您可以扩展被测类以使用新的模拟功能覆盖方法。因此，您可以扩展 Customer 并重写 callHttps()，这样它除了记录它被调用以便您可以验证它是否确实被调用之外，实际上不会执行任何操作。

请注意，我并不是提倡您应该像这样测试您的代码。通常使用此模式表示 code that could be restructured 。所以，如果可以的话，完全放弃继承权。话虽这么说，如果必须的话，请尝试使用类似于下面的示例代码的内容:

public class CustomerTest {
  @Mock
  private Observable<HttpClientResponse> mockObservable;

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

  @Test
  public void getCustomerDetailsCallsCallHttps() {
    CustomerSelfShunt customerUnderTest = new CustomerSelfShunt();
    // Call the getCustomerDetails method. Should call overridden version of
    // callHttps() that sets callHttpsInvoked.
    Observable<String> actualObservable = customerUnderTest.getCustomerDetails("foo");
    assertEquals(this.mockObservable, actualObservable);
    assertTrue(customerUnderTest.callHttpsInvoked);
  }

  private class CustomerSelfShunt extends Customer {
    boolean callHttpsInvoked = false;

    public Observable<HttpClientResponse> callHttps(String url, MultiMap headers, String body, HttpMethod httpMethod) {
      // do nothing implementation, just record that this method was called.
      callHttpsInvoked = true;
    }
  }
}