Android.os.Looper中未被嘲弄的方法getMainLooper即使在添加RxImmediateSchedulerRule之后仍会出现

Question

TrendingViewModelTest

@RunWith(JUnit4::class)
class TrendingViewModelTest {
    private lateinit var trendingRepository: TrendingRepository
    private lateinit var trendingViewModel: TrendingViewModel

    @get:Rule
    val schedulers = RxImmediateSchedulerRule()

    @Before
    fun setUp() {
        trendingRepository = mock(TrendingRepository::class.java)
        trendingViewModel = TrendingViewModel(trendingRepository)
    }

    @Test
    fun testWithNetwork() {
        trendingViewModel.isConnected = true
        trendingViewModel.fetchTrendingRepos()
        verify(trendingRepository, times(1)).getTrendingRepos()
    }

    //...
}

趋势视图模型

fun fetchTrendingRepos() {
if (isConnected) {
    loadingProgress.value = true
    compositeDisposable.add(
        trendingRepository.getTrendingRepos().subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe({ response ->
                run {
                    loadingProgress.value = false
            },
                { error ->
                    loadingProgress.value = false
                }
            )
    )
} 

class RxImmediateSchedulerRule : TestRule {
    override fun apply(base: Statement?, description: Description?): Statement {
        return object : Statement() {
            @Throws(Throwable::class)
            override fun evaluate() {
                RxJavaPlugins.setIoSchedulerHandler { Schedulers.trampoline() }
                RxJavaPlugins.setComputationSchedulerHandler { Schedulers.trampoline() }
                RxJavaPlugins.setNewThreadSchedulerHandler { Schedulers.trampoline() }
                RxAndroidPlugins.setInitMainThreadSchedulerHandler { Schedulers.trampoline() }

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

class TrendingRepositoryImpl @Inject constructor(
    val apiService: GitHubApi,
    val trendingDao: AppDao
) : TrendingRepository {

    override fun getTrendingRepos(): Single<List<TrendingRepo>> {
        return apiService.getTrendingGits()
    }
}

TrendingRepository：

interface TrendingRepository {
    fun getTrendingRepos(): Single<List<TrendingRepo>>
}

在FetchTrendingRepos()内部启动了一个Rxjava调用，它还挂钩到“AndroidSchedulers.MainThread（）”，这可能是导致它的原因。

Answer 1

在更新LiveData值时，还应添加@get:rule var rule:TestRule=InstantTaskExecutorRule()。

不要忘记在build.gradle文件中添加以下内容：

dependencies {
    // ...
    testImplementation "androidx.arch.core:core-testing:2.1.0"
}

此外，相应地更改测试代码，以避免NullPointerException:

@Test
fun testWithNetwork() {
    trendingViewModel.isConnected = true
    Mockito.`when`(trendingRepository.fetchTrendingRepos()).thenReturn(Single.just(listOf<TrendingRepo>()))
    trendingViewModel.fetchTrendingRepos()
    verify(trendingRepository, times(1)).getTrendingRepos()
}

mockito.when()允许您在每次调用模拟方法时执行不同的操作。如果不使用它，您可能会看到可能的NullPointerException取决于您的测试函数。