即使添加了RxImmediateSchedulerRule，仍然发生"android.os.Looper中的getMainLooper方法未模拟"的错误。

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()
    }

    //...
}

TrendingViewModel

的翻译是

热门趋势视图模型

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
                }
            )
    )
} 

RxImmediateSchedulerRule：

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()
                }
            }
        }
    }
}

TrendingRepositoryImpl：

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

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

热门仓库：

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

fetchTrendingRepos() 中启动了一个 Rxjava 调用，它也钩住 'AndroidSchedulers.mainThread()'，这可能是引起问题的原因。

java.lang.RuntimeException: 在 android.os.Looper 中方法 getMainLooper 未模拟。 at android.os.Looper.getMainLooper(Looper.java) at androidx.arch.core.executor.DefaultTaskExecutor.isMainThread(DefaultTaskExecutor.java:77) at androidx.arch.core.executor.ArchTaskExecutor.isMainThread(ArchTaskExecutor.java:116) at androidx.lifecycle.LiveData.assertMainThread(LiveData.java:461) at androidx.lifecycle.LiveData.setValue(LiveData.java:304) at androidx.lifecycle.MutableLiveData.setValue(MutableLiveData.java:50) at com.manoj.trendgitz.mvvm.ui.TrendingViewModel.fetchTrendingRepos(TrendingViewModel.kt:32) at com.manoj.trendgitz.TrendingViewModelTest.testWithNetwork(TrendingViewModelTest.kt:52) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17) at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268) at org.junit.runners.ParentRunner.run(ParentRunner.java:363) at org.junit.runner.JUnitCore.run(JUnitCore.java:137) at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68) at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47) at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242) at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)

- Manoj Perumarath

---

您能将运行测试时获得的所有日志都放在一起吗？ - Natig Babayev

添加了@NatigBabayev。 - Manoj Perumarath

Answer 1

当您更新LiveData的值时，还应添加 @get:Rule var rule: TestRule = InstantTaskExecutorRule()。

不要忘记将以下内容添加到build.gradle文件中：

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

此外，请相应更改您的测试代码以避免 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()函数允许您在每次调用模拟方法时执行不同的操作。如果您不使用它，则根据测试函数，可能会看到可能的NullPointerException。

- Natig Babayev

---

它引起了 java.lang.NullPointerException 在 com.manoj.trendgitz.mvvm.ui.TrendingViewModel.fetchTrendingRepos(TrendingViewModel.kt:34) 在 com.manoj.trendgitz.TrendingViewModelTest.testWithNetwork(TrendingViewModelTest.kt:53) @Natig Babayev - Manoj Perumarath

TrendingViewModel的第34行是什么？ - Natig Babayev

trendingRepository.getTrendingRepos().subscribeOn(Schedulers.io())，我也调试过了，它不是空的。 - Manoj Perumarath

很可能你忘记了Mockito.`when`(trendingRepository.fetchTrendingRepos()).thenReturn(...)。在调用viewModel函数之前添加它。 - Natig Babayev

我稍微更新了问题，@Natig Babayev - Manoj Perumarath

正是我所需要的，谢谢！ - Nicolas Mage

Answer 2

在你的应用程序的build.gradle文件中，在android{}下面添加以下代码：

testOptions {
            // Used for Unit testing Android dependent elements in /test folder
            unitTests.includeAndroidResources  = true
            unitTests.returnDefaultValues = true
        }

- Kanagalingam

---

添加后请重新运行所有测试。可能会出现意外的失败。 - divonas

Answer 3

首先添加testImplementation用于 core-testing。

testImplementation 'androidx.arch.core:core-testing:2.1.0'

然后在您的单元测试类中，在变量rule中添加一个InstantTaskExecutorRule。

import androidx.arch.core.executor.testing.InstantTaskExecutorRule

class TrendingViewModelTest {

     @get:Rule
     val rule = InstantTaskExecutorRule()

}

- Bayu Wijaya Permana Putra

Answer 4

如果您在没有添加RxImmediateSchedulerRule的情况下看到此错误，请尝试将此规则添加到您的测试类中：

@Rule @JvmField
val instantTaskExecutorRule = InstantTaskExecutorRule()

- divonas