Question

我有一个SingleLiveEvent<Void>变量。从api获得响应后，我将其发布。我的回调被调用，并显示一个弹出窗口。我的问题是如何编写测试用例进行检查，是否显示弹出窗口。

现场活动：

private SingleLiveEvent<Void> onAccountOverDrawn = new SingleLiveEvent<>();

成功响应时，我打电话给：

onAccountOverDrawn.post();

在我的片段中，我将其注册为

viewModel.getOnAccountOverDrawn().observe(this, aVoid -> onAccountOverDrawn());

，在onAccountOverDrawn()中，我只是显示一个弹出窗口。

那么我将如何为这种情况编写一个测试用例？

当前测试用例：

@Test
public void updateApplicationStatus_AccountOverdrawn() {
    viewModel.updateApplicationStatus("AMOUNT_PENDING");

    assertNotNull(viewModel.getOnAccountOverDrawn()); //this line is of no use. Need to change this.
}

Answer 1

如果要测试是否有弹出窗口，可以使用Robolectric。

Answer 2

如果要测试是否已观察到实时数据，可以使用以下测试

private LifecycleOwner lifecycleOwner;
MutableLiveData<Boolean> mutableLiveData = new MutableLiveData(); //Live data to be observed from viewModel
@Mock
private Lifecycle lifecycle;

    @Before
    public void setup() {
        lifecycleOwner = getLifecycleOwner();
PowerMockito.when(lifecycle.getCurrentState()).thenReturn(Lifecycle.State.CREATED);
    }


 @Test
    public void test() {

        mutableLiveData.observe(lifecycleOwner, new Observer<Boolean>() {
            @Override
            public void onChanged(@Nullable Boolean aBoolean) {
                assertTrue(aBoolean);
            }
        });
        mutableLiveData.postValue(true);
    }


private LifecycleOwner getLifecycleOwner() {
        return new LifecycleOwner() {
            @NonNull
            @Override
            public Lifecycle getLifecycle() {
                return lifecycle;
            }
        };
    }

Answer 3

我这样解决这个问题：

获取LiveData并订阅我们的模拟观察器。
调用应在ViewModel内部更改LiveData的方法。
检查我们的模拟观察器是否已接收到更新的数据。
检查此模拟观察器是否有更多更改。
检查如果我们在同一LiveData上重新订阅此模拟观察器，那么我们不会收到数据

请参见下面的代码：

@RunWith(MockitoJUnitRunner.class)
public class SomeFeatureViewModelTest {

    private SomeFeatureViewModel mSomeFeatureViewModel;

    // Rule for help testing. Just trust me you need it :)
    @Rule
    public InstantTaskExecutorRule mRule = new InstantTaskExecutorRule();

    @Mock
    private Observer<Void> mOnClickButtonEventObserver;

    @Before
    public void setup() {
        mSomeFeatureViewModel = new SomeFeatureViewModel();
    }

    @Test
    public void clickOnNextScreenButton() {

        // get LiveData and subscribe our observer to it:
        mSomeFeatureViewModel.getOnClickButtonEvent().observeForever(mOnClickButtonEventObserver);

        // call the method that should change the LiveData inside the ViewModel:
        mSomeFeatureViewModel.clickOnNextScreenButton();

        // check that our observer received the updated data:
        verify(mOnClickButtonEventObserver).onChanged(null);

        // check that there were no more changes of this observer:
        verifyNoMoreInteractions(mOnClickButtonEventObserver);

        // check that if we re-subscribe this observer on the same LiveData then we do not receive data:
        mSomeFeatureViewModel.getOnClickButtonEvent().observeForever(mOnClickButtonEventObserver);
        verifyNoMoreInteractions(mOnClickButtonEventObserver);

    }

}

如何测试SingleLiveEvent <void>变量？

3 个答案: