viewModel和livedata Mockito android的单元测试

Question

@Test
fun getNews() {

    Mockito.`when`(mainRepository.getNews()).thenReturn(Observable.just(getMockResponse()))
    //It is working good

    Mockito.`when`(networkHelper.isNetworkConnected()).thenReturn(true)
    //It is working good

    viewModel.getNews()

    assertEquals(Resource.success(getList()), viewModel.newsResponse.value)
}

 val newsResponse by lazy { SingleLiveEvent<Resource<List<RowsItem>>>() }

        fun getNews() {
        if (!networkHelper.isNetworkConnected()) { //It is true as we macked in Test Clas
            newsResponse.value = Resource.error(AppError.NetworkError)
            return
        }
        newsResponse.value = Resource.loading() // Crashing here when we are assigning value to live data: newsResponse
        val api = mainRepository.getNews().map {
            it.rows
        }

        val disposable = api.subscribeOn(Schedulers.computation())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe(
                { result -> handleResults(result) },
                { error -> handleError(error) },
            )

        compositeDisposable.add(disposable)
    }


     private fun handleResults(list: ArrayList<RowsItem>?) {
         if (list != null) {
             newsResponse.value = Resource.success(list)
 
         } else {
             newsResponse.value = Resource.error(AppError.CommonError)
         }
     }

      private fun handleError(t: Throwable?) {
          newsResponse.value = Resource.error(t?.failureAppError() ?: AppError.CommonError)
      }

进程结束，退出代码-1

Answer 1

只需要在测试类中添加规则

@Rule
@JvmField
var testSchedulerRule = RxImmediateSchedulerRule() //For Retrofit

@get:Rule
var instantTaskExecutorRule = InstantTaskExecutorRule()//For LiveData

RximediateSchedulerRule是扩展TestRule的自定义类

class RxImmediateSchedulerRule : TestRule {

private val immediateScheduler = object : Scheduler() {
    @NonNull
    override fun scheduleDirect(@NonNull run: Runnable, delay: Long, @NonNull unit: TimeUnit): Disposable {
        // Hack to prevent stack overflows in unit tests when scheduling with a delay;
        return super.scheduleDirect(run, 0, unit)
    }

    @NonNull
    override fun createWorker(): Worker {
       return ExecutorScheduler.ExecutorWorker(Executor { it.run() })
    }
}

@NonNull
override fun apply(@NonNull base: Statement, @NonNull description: Description): Statement {
    return object : Statement() {
        @Throws(Throwable::class)
        override fun evaluate() {
            RxJavaPlugins.setInitIoSchedulerHandler { immediateScheduler }
            RxJavaPlugins.setInitComputationSchedulerHandler { immediateScheduler }
            RxJavaPlugins.setInitNewThreadSchedulerHandler { immediateScheduler }
            RxJavaPlugins.setInitSingleSchedulerHandler { immediateScheduler }
            RxAndroidPlugins.setInitMainThreadSchedulerHandler { immediateScheduler }

            try {
                base.evaluate()
            } finally {
                RxJavaPlugins.reset()
                RxAndroidPlugins.reset()
            }
        }
    }
}}

现在，在最后，我的测试类看起来像

 @RunWith(MockitoJUnitRunner::class)
 class MainActivityViewModelTest : TestCase() {


private val networkHelper = Mockito.mock(NetworkHelper::class.java)

private val mainRepository = Mockito.mock(MainRepository::class.java)

private val viewModel = MainActivityViewModel(networkHelper, mainRepository)

@Rule
@JvmField
var testSchedulerRule = RxImmediateSchedulerRule() //For Retrofit

@get:Rule
var instantTaskExecutorRule = InstantTaskExecutorRule()//For LiveData


@Before
public override fun setUp() {

}

@Test
fun getNews() {
    Mockito.`when`(mainRepository.getNews()).thenReturn(Observable.just(getMockResponse()))
    //It is working good
    Mockito.`when`(networkHelper.isNetworkConnected()).thenReturn(true)

    //It is working good
    viewModel.getNews()

    assertEquals(Resource.success(getList()), viewModel.newsResponse.value)


}

private fun getMockResponse(): ApiResponse<ArrayList<RowsItem>> {
    return ApiResponse("Response Success", getList())
}

private fun getList(): ArrayList<RowsItem> {
    val rowsItem = RowsItem("ImageHref", "Desc", "Title")
    val list = ArrayList<RowsItem>()
    list.add(rowsItem)
    return list
}}