由于数据绑定，浓缩咖啡测试失败

Question

这是我的视图模型类：

class MainViewModel(
private val schedulerProvider: BaseSchedulerProvider,
private val api : StorytelService
) : BaseViewModel() {
private val _posts = MutableLiveData<List<Post>>()
val posts: LiveData<List<Post>>
get() = _posts
private val _status = MutableLiveData<Status>()
val status: LiveData<Status>
get() = _status
init {
showPhotos()
}
fun showPhotos() {
EspressoIdlingResource.increment() // App is busy until further notice
_status.postValue(Status.LOADING)
compositeDisposable.add(api.getPhotos()
.subscribeOn(schedulerProvider.io())
.observeOn(schedulerProvider.ui())
.doFinally {
if (!EspressoIdlingResource.countingIdlingResource.isIdleNow) {
EspressoIdlingResource.decrement() // Set app as idle.
}
}
.subscribe({
_status.postValue(Status.SUCCESS)
showPosts(it)
}) {
_status.postValue(Status.ERROR)
Timber.e(it)
})
}
private fun showPosts(networkPhotos: List<NetworkPhoto>) {
EspressoIdlingResource.increment() // App is busy until further notice
_status.postValue(Status.LOADING)
compositeDisposable.add(api.getPosts()
.subscribeOn(schedulerProvider.io())
.observeOn(schedulerProvider.ui())
.doFinally {
if (!EspressoIdlingResource.countingIdlingResource.isIdleNow) {
EspressoIdlingResource.decrement() // Set app as idle.
}
}
.subscribe({ networkPosts ->
_status.postValue(Status.SUCCESS)
_posts.postValue(
PostAndImages(networkPosts, networkPhotos).asDomaineModel()
)
}) {
_status.postValue(Status.ERROR)
Timber.e(it)
})
}

这是我的回收器布局视图：

<androidx.recyclerview.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
app:showData="@{vm.status}"
tools:listitem="@layout/post_item" />

这是绑定适配器：

@BindingAdapter("showData")
fun View.showData(status: Status) {
visibility = if (status == Status.SUCCESS) View.VISIBLE else View.GONE
}

正如您注意到的，我正在使用EspressoIdlingResource，但是当我运行以下浓缩咖啡测试时，它失败了：

@Test
fun shouldBeAbleToLoadList() {
onView(withId(R.id.recycler_view)).check(matches(isDisplayed()))
} 

如果我在测试开始时添加 Thread.sleep(5000(，它可以工作。如何解决？

Answer 1

Idling Resource应该是可能的，但它们有点乏味。

我刚刚更新了一个旧的 viewMatcher 代码：

/**
* Perform action of waiting for a specific view id to be displayed.
* @param viewId The id of the view to wait for.
* @param millis The timeout of until when to wait for.
*/
public static ViewAction waitDisplayed(final int viewId, final long millis) {
return new ViewAction() {
@Override
public Matcher<View> getConstraints() {
return isRoot();
}
@Override
public String getDescription() {
return "wait for a specific view with id <" + viewId + "> has been displayed during " + millis + " millis.";
}
@Override
public void perform(final UiController uiController, final View view) {
uiController.loopMainThreadUntilIdle();
final long startTime = System.currentTimeMillis();
final long endTime = startTime + millis;
final Matcher<View> matchId = withId(viewId);
final Matcher<View> matchDisplayed = isDisplayed();
do {
for (View child : TreeIterables.breadthFirstViewTraversal(view)) {
if (matchId.matches(child) && matchDisplayed.matches(child)) {
return;
}
}
uiController.loopMainThreadForAtLeast(50);
}
while (System.currentTimeMillis() < endTime);
// timeout happens
throw new PerformException.Builder()
.withActionDescription(this.getDescription())
.withViewDescription(HumanReadables.describe(view))
.withCause(new TimeoutException())
.build();
}
};
}

那么你只应该做：

@Test
fun shouldBeAbleToLoadList() {
onView(isRoot()).perform(waitDisplayed(R.id.recycler_view, 5000));
} 

5000是 5 秒(5000 毫秒(的超时，您可以根据需要进行更改。

执行waitDisplayed后，可能会显示元素或达到超时。在最后一种情况下，将抛出Exception。

Answer 2

您需要为绑定创建一个Idling Resource。 您可以查看具有类似实现的 Android 架构组件示例。以下是您需要查找的内容：

1. 首先，您需要添加一个Idling Resource类来检查是否有任何绑定挂起(您可以在此处找到实现(
2. 现在，您可以创建一个规则，该规则将自动为您注册/取消注册Idling Resource(您可以在此处找到实现(。
3. 现在，您可以将此规则添加到测试中并检查它是否有效(您可以在此处找到示例测试实现(。