测试异步RxJava代码 – Android

场景很简单.

>我通过进行REST调用来获取UserInfo对象
>如果重新调整的UserInfo对象不为null,则返回true,否则返回false.

对于上面的场景,我的RxJava代码看起来像这样

public LiveData<Boolean> doesUserExists(String userName) {
    UserExistsObserver observer= new UserExistsObserver ();
    getUserInfo(userName).subscribeWith(subscriber);
    disposable.add(observer);
    return userExists;
}

public Observable<Boolean> getUserInfo(String userName) {
    return repository.getUserInfo(userName)
            .flatMap(new Function<UserInfo,Observable<Boolean>>() {
                @Override
                public Observable<Boolean> apply(UserInfo userInfo) throws Exception {
                      return Observable.just(userInfo != null);
                }
            })
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread());
}

所以我想编写一个简单的单元测试来检查getUserInfo()是否返回正确的布尔值.以下是我的单元测试.

@Test
public void getUserInfo_returns_true(){
    UserInfo userInfo = new UserInfo(); //Dummy data - non null userInfo object
    when(repository.getUserInfo("username")).thenReturn(Observable.just(userInfo));

    TestObserver<Boolean> testObserver = new TestObserver<>();
    //the flatMap operator should return true since userInfo is not null
    viewModel.getUserInfo("username").subscribeWith(testObserver); 
    testObserver.assertValue(true);
}

以下是我的日志

java.lang.AssertionError: Expected: true (class: Boolean),Actual: [] (latch = 1,values = 0,errors = 0,completions = 0)

at io.reactivex.observers.BaseTestConsumer.fail(BaseTestConsumer.java:163)
at io.reactivex.observers.BaseTestConsumer.assertValue(BaseTestConsumer.java:328)
at com.ik.githubbrowser.search_user.SearchUserViewModelTest.getUserInfo_returns_true(SearchUserViewModelTest.java:51)
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.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
at org.junit.rules.TestWatcher$1.evaluate(TestWatcher.java:55)
at org.junit.rules.RunRules.evaluate(RunRules.java:20)
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.mockito.internal.runners.JUnit45AndHigherRunnerImpl.run(JUnit45AndHigherRunnerImpl.java:37)
at org.mockito.runners.MockitoJUnitRunner.run(MockitoJUnitRunner.java:62)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:117)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:42)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:262)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:84)
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 com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

java.lang.NullPointerException
at io.reactivex.android.schedulers.HandlerScheduler$HandlerWorker.schedule(HandlerScheduler.java:70)
at io.reactivex.Scheduler$Worker.schedule(Scheduler.java:272)
at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.schedule(ObservableObserveOn.java:161)
at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.onNext(ObservableObserveOn.java:119)
at io.reactivex.internal.operators.observable.ObservableSubscribeOn$SubscribeOnObserver.onNext(ObservableSubscribeOn.java:58)
at io.reactivex.internal.operators.observable.ObservableScalarXMap$ScalarDisposable.run(ObservableScalarXMap.java:248)
at io.reactivex.internal.operators.observable.ObservableScalarXMap$ScalarXMapObservable.subscribeActual(ObservableScalarXMap.java:164)
at io.reactivex.Observable.subscribe(Observable.java:10903)
at io.reactivex.internal.operators.observable.ObservableSubscribeOn$SubscribeTask.run(ObservableSubscribeOn.java:96)
at io.reactivex.Scheduler$DisposeTask.run(Scheduler.java:452)
at io.reactivex.internal.schedulers.ScheduledRunnable.run(ScheduledRunnable.java:61)
at io.reactivex.internal.schedulers.ScheduledRunnable.call(ScheduledRunnable.java:52)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

Exception in thread "RxCachedThreadScheduler-1" java.lang.NullPointerException
at io.reactivex.android.schedulers.HandlerScheduler$HandlerWorker.schedule(HandlerScheduler.java:70)
at io.reactivex.Scheduler$Worker.schedule(Scheduler.java:272)
at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.schedule(ObservableObserveOn.java:161)
at io.reactivex.internal.operators.observable.ObservableObserveOn$ObserveOnObserver.onNext(ObservableObserveOn.java:119)
at io.reactivex.internal.operators.observable.ObservableSubscribeOn$SubscribeOnObserver.onNext(ObservableSubscribeOn.java:58)
at io.reactivex.internal.operators.observable.ObservableScalarXMap$ScalarDisposable.run(ObservableScalarXMap.java:248)
at io.reactivex.internal.operators.observable.ObservableScalarXMap$ScalarXMapObservable.subscribeActual(ObservableScalarXMap.java:164)
at io.reactivex.Observable.subscribe(Observable.java:10903)
at io.reactivex.internal.operators.observable.ObservableSubscribeOn$SubscribeTask.run(ObservableSubscribeOn.java:96)
at io.reactivex.Scheduler$DisposeTask.run(Scheduler.java:452)
at io.reactivex.internal.schedulers.ScheduledRunnable.run(ScheduledRunnable.java:61)
at io.reactivex.internal.schedulers.ScheduledRunnable.call(ScheduledRunnable.java:52)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

Process finished with exit code -1