如何使viewModelScope在单元测试中等待挂起函数

Question

正如我们所知，viewModelScope的默认调度程序是并行执行的。如何使viewModelScope在单元测试中等待挂起函数。在我的代码中，我想从repository.getData()获得结果，这样我的断言就通过了。现在，我没有按时得到结果。

class MainViewModel(private val repository: Repository,
private val dispatcher: CoroutineDispatcherProvider) : ViewModel() {
private val viewState = MutableLiveData<Results<Data>>()
fun getViewState() : LiveData<Results<Data>> = viewState

fun getData(query: search) {
viewState.value = Loading
viewModelScope.launch(dispatcher.main()) {
val results = repository.getData(query) //need to wait for this
when(results){
is Success -> {
viewState.value = Success(results.data)
}
is Error -> viewState.value = Error(“Error”)
}
}

MainViewModelTest:

Class MainViewModelTest {
@get:Rule
val instantExecutorRule = InstantTaskExecutorRule()
@get:Rule
val coroutineTestRule = CoroutineTestRule()

@Test
fun `test get data`() = coroutineTestRule.testCoroutineDispatcher.runBlockingTest {
coEvery{repository.getData(“query”)} returns Success(Data)
var observer:Observer<Results<Data>> = mock()
viewModel.getViewState().observeForever(observer)
viewModel.getData(“query”)
assertEquals(Loading, state)
assertEquals(resultSuccess, state)
}
}

Answer 1

我认为应该使用observer.onChanged()进行断言和验证。我认为没有其他问题。

val successResult = Result.Success(Data)
coEvery{repository.getData(“query”)} returns successResult
verify { observer.onChanged(Result.Loading) }
verify { observer.onChanged(successResult) }