测试 RxJava2 doOnComplete()

Question

如下所示的代码，我试图测试存储库中发生的doOnComplete()调用的行为。但是，当我模拟注入的依赖项时，我使用Observable.just()返回项目，doOnComplete()不再被调用。我相信这是RxJava2故意为之。我不确定如何解决这个问题。

@Singleton
public class Repository {
    private SomeNetworkClient client;
    private SomeCache cache;

    @Inject
    public Repository(SomeNetworkClient client, SomeCache cache) {
        this.client = client;
        this.cache = cache;
    }

    public Observable<SomeItem> getSomeItem() {
        return client.getSomeItem()
                .doOnComplete(() -> cache.doThisOnComplete())
                .doOnError(throwable -> someError);
    }
}

public class RepositoryTest {
    private Repository testedRepository;
    @Mock
    SomeNetworkClient client;
    @Mock
    SomeCache cache;
    @Mock
    SomeItem someItem;

    @Before
    public void setup() {
        MockitoAnnotations.initMocks(this);
        testedRepository = new Repository(client, cache);
        when(client.getSomeItem())
            .thenReturn(Observable.just(someItem));
    }

    @Test
    public void thisTestFails() {
        testedRepository.getSomeItem().blockingFirst();
        // This fails because it appears that mocking with
        // Observable.just() makes doOnComplete() not be invoked.
        verify(cache.doThisOnComplete());
    }
}

- Timothy Duch

Answer 1

你代码中的问题是，blockingFirst() 不会等待 complete 事件发生。它会立即从流中返回第一个 item 并 取消 observable。

相反，你可以这样进行断言：

    testedRepository
            .getSomeItem()
            .test()
            .assertComplete()

- azizbekian