android - MockK 模拟 ViewModel 的 savedStateHandle.getLiveData()
问题描述
我正在尝试使用 savedStateHandle 测试这个 ViewModel
class PostListViewModel @ViewModelInject constructor(
private val coroutineScope: CoroutineScope,
private val getPostsUseCase: GetPostListUseCaseFlow,
@Assisted savedStateHandle: SavedStateHandle
) : AbstractPostListVM() {
private val _goToDetailScreen =
savedStateHandle.getLiveData<Event<Post>>(POST_DETAIL)
// MutableLiveData<Event<Post>>()
override val goToDetailScreen: LiveData<Event<Post>>
get() = _goToDetailScreen
private val _postViewState =
savedStateHandle.getLiveData<ViewState<List<Post>>>(POST_LIST)
// MutableLiveData<ViewState<List<Post>>>()
override val postViewState: LiveData<ViewState<List<Post>>>
get() = _postViewState
override fun getPosts() {
getPostsUseCase.getPostFlowOfflineFirst()
.convertToFlowViewState()
.onStart {
_postViewState.value = ViewState(status = Status.LOADING)
}
.onEach {
_postViewState.value = it
}
.launchIn(coroutineScope)
}
override fun refreshPosts() {
getPostsUseCase.getPostFlowOfflineLast()
.convertToFlowViewState()
.onStart {
_postViewState.value = ViewState(status = Status.LOADING)
}
.onEach {
_postViewState.value = it
}
.launchIn(coroutineScope)
}
override fun onClick(post: Post) {
_goToDetailScreen.value = Event(post)
}
}
测试是
@Test
fun `given exception returned from useCase, should have ViewState ERROR offlineFirst`() =
testCoroutineRule.runBlockingTest {
// GIVEN
every {
savedStateHandle.getLiveData<ViewState<List<Post>>>(AbstractPostListVM.POST_LIST)
} returns MutableLiveData()
every {
savedStateHandle.getLiveData<Event<Post>>(AbstractPostListVM.POST_DETAIL)
} returns MutableLiveData()
every {
useCase.getPostFlowOfflineFirst()
} returns flow<List<Post>> {
emit(throw Exception("Network Exception"))
}
val testObserver = viewModel.postViewState.test()
// WHEN
viewModel.getPosts()
// THEN
testObserver
.assertValue { states ->
(states[0].status == Status.LOADING &&
states[1].status == Status.ERROR)
}
.dispose()
val finalState = testObserver.values()[1]
Truth.assertThat(finalState.error?.message).isEqualTo("Network Exception")
Truth.assertThat(finalState.error).isInstanceOf(Exception::class.java)
verify(atMost = 1) { useCase.getPostFlowOfflineFirst() }
}
当我使用MutableLiveData
而不是SavedStateHandle.getLiveData()
与此测试和其他测试一起使用时,此测试有效。
将 savedStateHandle 嘲笑为
private val savedStateHandle: SavedStateHandle = mockk()
返回
io.mockk.MockKException: no answer found for: SavedStateHandle(#2).getLiveData(POST_LIST)
我将模拟的 savedStateHandle 更改为 withrelaxed = true
private val savedStateHandle: SavedStateHandle = mockk(relaxed = true)
基于这个问题。
现在 postViewState 的值不会改变并且测试失败
java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
模拟和获取 LiveData 的正确方法是什么SavedStateHandle
?
解决方案
也许是因为我使用junit5,选择的答案对我不起作用。
如果它对某人有帮助,我所做的是SavedStateHandle
使用我需要的信息创建一个实例,而不是在测试的第一部分(在 Given/Arrange 部分)模拟它,然后初始化 ViewModel:
@Test
fun `whatever`() =
coroutineRule.testDispatcher.runBlockingTest {
val savedStateHandle = SavedStateHandle().apply {
set(MyViewModel.KEY, "something")
}
val viewModel = PostListViewModel(coroutineScope, getPostsUseCase, savedStateHandle)
...
}
推荐阅读
- python - 使用数组过滤器更新 MongoDB
- graphics - GLSL 计算着色器仅部分写入 Vulkan 中的缓冲区
- c++ - 来自 STL 优先级队列 C++ (QtCreator) 的打印结构
- java - 光标为空,但查询(假设)正确
- date - Dateish 字符串的问题
- python - Python OpenCV 3.4 VideoWriter 问题
- pandas - 合并在 Pandas 中的行为不符合预期
- javascript - 选择的选项不显示。也许是angularjs问题?
- ios - 通过 ARKit 向 3d 模型添加动画
- java - 无循环打印 Arraylist