测试异步RxJava代码 - Android

时间：2017-10-03 16:35:15

标签： android unit-testing asynchronous rx-java rx-java2

我正在了解RxJava。我开始在我的一个个人应用程序中使用它，并希望单元测试代码，但有一些困难，并希望得到一些帮助。

情景很简单。

  1. 通过进行REST调用获得UserInfo个对象
  2. 如果重新调整的UserInfo对象不为null，则返回true，否则返回false。

    3. 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

3 个答案:

答案 0 :(得分：10)

您的方法必须通过2个不同的线程来生成结果（由于subscribeOn和observeOn调用）。这意味着观察者需要时间来实际产生结果。在检查TestObserver.awaitTerminalEvent()之前使用assertValue以确保observable实际产生了值。

或者，在测试代码时，您应该使用不同的调度程序，因为Android调度程序可能需要额外的代码才能在测试环境中正常运行。

答案 1 :(得分：8)

正如@kiskae建议我必须更换调度程序。我替换了subscribeOn和observeOn调度程序。我们的想法是在同一个线程上执行操作，从而使其同步。由于此单元测试在JVM上运行，因此JVM将无法访问作为调度程序传递给AndroidSchedulers.mainThread()的Android特定observeOn。所以我们在RxAndroidPlugins类的帮助下替换了这个调度程序。我们也使用subscribeOn类替换传递给RxJavaPlugins的调度程序。

欲了解更多信息，请阅读this中等帖子。

以下是我的工作代码。

import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.MockitoAnnotations;
import org.mockito.runners.MockitoJUnitRunner;

import java.util.concurrent.Callable;

import io.reactivex.Observable;
import io.reactivex.Scheduler;
import io.reactivex.android.plugins.RxAndroidPlugins;
import io.reactivex.annotations.NonNull;
import io.reactivex.functions.Function;
import io.reactivex.observers.TestObserver;
import io.reactivex.plugins.RxJavaPlugins;
import io.reactivex.schedulers.Schedulers;

import static org.mockito.Matchers.anyString;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

@RunWith(MockitoJUnitRunner.class) 
public class SearchUserViewModelTest {

    private RepositoryImpl repository;
    private SearchUserViewModel viewModel;

@BeforeClass
public static void before(){
    RxAndroidPlugins.reset();
    RxJavaPlugins.reset();
    RxJavaPlugins.setIoSchedulerHandler(new Function<Scheduler, Scheduler>() {
        @Override
        public Scheduler apply(@NonNull Scheduler scheduler) throws Exception {
            return Schedulers.trampoline();
        }
    });
    RxAndroidPlugins.setInitMainThreadSchedulerHandler(new Function<Callable<Scheduler>, Scheduler>() {
        @Override
        public Scheduler apply(@NonNull Callable<Scheduler> schedulerCallable) throws Exception {
            return Schedulers.trampoline();
        }
    });
}


@Before
public void setup(){

    MockitoAnnotations.initMocks(this);
    repository = mock(RepositoryImpl.class);
    viewModel = new SearchUserViewModel(repository);
}

@Test
public void getUserInfo_returns_true(){
    UserInfo userInfo = new UserInfo();
    userInfo.setName("");
    when(repository.getUserInfo(anyString())).thenReturn(Observable.just(userInfo));
    TestObserver<Boolean> testObserver = new TestObserver<>();
    viewModel.getUserInfo(anyString()).subscribe(testObserver);
    testObserver.assertValue(true);
}

@AfterClass
public static void after(){
    RxAndroidPlugins.reset();
    RxJavaPlugins.reset();
}

}

答案 2 :(得分：1)

通过定义新的测试规则，您可以保持测试类的干净，并再次在其他测试类中使用此规则

public class RxSchedulerRule implements TestRule {
 @Override
 public Statement apply(Statement base, Description description) {

    return new Statement() {
        @Override
        public void evaluate() throws Throwable {
            RxAndroidPlugins.setInitMainThreadSchedulerHandler(schedulerCallable
                    -> TrampolineScheduler.instance());
            RxJavaPlugins.setIoSchedulerHandler(scheduler
                    -> TrampolineScheduler.instance());
            RxJavaPlugins.setComputationSchedulerHandler(scheduler ->
                    TrampolineScheduler.instance());

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

        }
    };
 }
}

在您的测试课程中

@Rule
public RxSchedulerRule rxSchedulerRule=new RxSchedulerRule();
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