用DaggerMock模拟依赖组件的依赖关系

Question

我想为一个应用程序编写Espresso测试，所以我尝试DaggerMock来模拟一些外部依赖，比如本地存储。

我的Dagger设置由一个带有3个模块(DatabaseModule、DataModule和ApplicationModule)的ApplicationComponent组成，对于屏幕( Fragment )，我想测试的还有另一个依赖于ApplicationComponent的组件。

到目前为止，我尝试的是：

@Rule public DaggerMockRule<ApplicationComponent> daggerRule =
        new DaggerMockRule<>(ApplicationComponent.class, new DatabaseModule(), new DataModule(application),
                new ApplicationModule(application)).set(
                component -> {
                    MyApplication app =
                            (MyApplication) InstrumentationRegistry.getInstrumentation()
                                    .getTargetContext()
                                    .getApplicationContext();
                    app.setComponent(component);
                });

@Rule
public final DaggerMockRule<FeedComponent> rule = new DaggerMockRule<>(
        FeedComponent.class, new FeedDataSourceModule(),
        new FeedDownloadImageUseCaseModule(), new FeedServiceModule(), new FeedPresenterModule(null))
        .addComponentDependency(ApplicationComponent.class, new DatabaseModule(), new DataModule(application), new ApplicationModule(application))
        .set(component -> localDataSource = component.localDataSource());

@Mock FeedDao feedDao;

@Mock NetworkUtils networkUtils;

@Mock FeedLocalDataSource localDataSource;

其中localDataSource实际上是我想要模拟的依赖项，它是在FeedDataSourceModule中构建的：

@Module
public class FeedDataSourceModule {

@Provides
@FragmentScope
public FeedItemMapper providesFeedItemMapper() {
    return new FeedItemMapper();
}

@Provides
@FragmentScope
public FeedLocalDataSource providesFeedLocalDataSource(FeedDao feedDao, FeedRequestDetailsDao detailsDao, FeedItemMapper mapper) {
    return new FeedLocalDataSourceImpl(feedDao, detailsDao, mapper);
}

@Provides
@FragmentScope
public FeedRemoteDataSource providesFeedRemoteDataSource(FeedService feedService, FlagStateService flagStateService,
          @Named("Api-Token") String apiToken, @Named("Screen-Size") String screenSize,
                                                  @Named("Account-Id") String accountId) {
    return new FeedRemoteDataSourceImpl(feedService, flagStateService, apiToken, screenSize, accountId);
}

}

还有依赖于FeedComponent的ApplicationComponent：

@FragmentScope
@Component( dependencies = ApplicationComponent.class,
        modules = {
            FeedPresenterModule.class,
            FeedServiceModule.class,
            FeedDataSourceModule.class,
            FeedDownloadImageUseCaseModule.class})
public interface FeedComponent {

@Named("Api-Token") String getApiToken();

@Named("Api-Key") String getApiKey();

FeedLocalDataSource localDataSource();

FeedRemoteDataSource remoteDataSource();

void inject(FeedFragment feedFragment);
}

通过上面发布的两个@Rules，我可以确认NetworkUtils似乎确实被正确地模仿了，因为我使用了Mockito.when()来返回false值，并且通过在代码中使用断点，我可以看到值始终是假的：

    when(networkUtils.isOnline())
            .thenReturn(false);

但是对于localDataSource来说不是这样，虽然我声明了：

    when(localDataSource.getFeedSorted())
            .thenReturn(Flowable.just(feedList));

为了防止有帮助，我是这样从FeedComponent注入依赖关系的：

            DaggerFeedComponent.builder()
                .applicationComponent(MyApplication.getApplicationComponent())
                .feedPresenterModule(new FeedPresenterModule(this))
                .build()
                .inject(this);

Answer 1

为什么在测试中使用两个DaggerMock规则？我认为您可以使用一个规则，比如在这个示例中。