android - 使用 Mockito 进行 JVM 单元测试以测试网络请求的 Retrofit2 和 RxJava

Question

Android Studio 2.3 RC 1

我正在使用 MVP 架构并希望运行 JVM 单元测试。

在我的模型中，我使用 Retrofit2 和 RxJava 从 API 获取电影。我想测试函数 getPopularMovies(...) 但是，此函数将调用网络服务器。然而，在测试中我想以某种方式模拟它并测试 onSuccess() 和 onFailure() 方法被调用。

我的模型类看起来像这个 fragment 只是为了保持简短:

public class MovieListModelImp implements MovieListModelContract {

    @Override
    public void getPopularMovies(PopularMovieResultsListener popularMovieResultsListener) {
        mSubscription = mMovieAPIService.getPopular(Constants.MOVIES_API_KEY)
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Subscriber<Results>() {
            @Override
            public void onCompleted() {
                Timber.d("onCompleted");
            }

            @Override
            public void onError(Throwable e) {
                Timber.e(e, "onError");
                popularMovieResultsListener.onFailure(e.getMessage());
            }

            @Override
            public void onNext(Results results) {
                Timber.d("onNext %d", results.getResults().size());
                popularMovieResultsListener.onSuccess(results);
            }
        });
    }
}

界面:

public interface MovieListModelContract {
    interface PopularMovieResultsListener {
        void onFailure(String errorMessage);
        void onSuccess(Results popularMovies);
    }
    void getPopularMovies(PopularMovieResultsListener popularMovieResultsListener);
}

我要解决的问题是如何在不实际调用网络服务的情况下使用 Mockito 测试 getPopularMovies？我只想测试一下:popularMoviesResultsListener.onFailure(e.getMessage()) 获取电影失败时调用和popularMovieResultsListener.onSuccess(results); 接收到电影成功时调用

我有这样的测试，但我不确定这是否正确:

@Test
public void shouldDisplaySuccessWhenNetworkSucceeds() {
    /* Results is the movie results class that is returned */
    Results results = new Results();

    /* Mock the listener */
    MovieListModelContract.PopularMovieResultsListener mockPopularMoviesResultsListener =
            Mockito.mock(MovieListModelContract.PopularMovieResultsListener.class);

    /* Real instance of the model */
    MovieListModelImp movieListModelImp = new MovieListModelImp();

    /* Call getPopularMovies with mock listener - However, this will still make a real network request */
    movieListModelImp.getPopularMovies(mockPopularMoviesResultsListener);

    /* Verify - but I think I have got this all wrong */
    verify(mockPopularMoviesResultsListener, times(1)).onSuccess(results);
}

所以我的问题是如何模拟对网络请求的调用并测试预期的 onSuccess() 和 onFailure() 是否正常工作？

Answer 1

这个想法是让用户 TestSubscriber 在单元测试中断言。

Return the Observable from Retrofit instead of void

(请注意，我已经删除了监听器 PopularMovieResultsListener，因为您正在使用 RxJava。使用 RxJava，您可以订阅返回的 Observable 并使用 onNext()， onComplete()，onError() 代替。)

public class MovieListModelImp implements MovieListModelContract {

    @Override
    public Observable<Results> getPopularMovies() {
        /** Return the Observable from Retrofit. */
        return mMovieAPIService.getPopular(Constants.MOVIES_API_KEY);
}

Use TestSubscriber in your unit tests to assert

@Mock
MovieAPIService mMovieAPIService

@Test
public void shouldDisplaySuccessWhenNetworkSucceeds() {

    /* Results is the movie results class that is returned */
    Results expectedResults = new Results();


    MovieListModelImp movieListModelImp = new MovieListModelImp();
    //Mock mMovieAPIService which is the actual network call
    when(mMovieAPIService.getPopular(any(String.class)).thenReturn(Observable.just(results));

    Observable<Results> actualResultsObservable = movieListModelImp.getPopularMovies();
    TestObserver<Results> testObserver = actualResultsObservable.test();
    testObserver.assertSubscribed();

    testObserver.assertResult(expectedResults);

    //verify
    verify(mMovieAPIService, times(1)).getPopular(any(String.class));

}