code: /*
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.rxjava3.internal.operators.observable;
  
  import static org.junit.Assert.*;
  import static org.mockito.Mockito.*;
  
  import java.io.IOException;
  import java.util.*;
  import java.util.concurrent.*;
  import java.util.concurrent.atomic.*;
  
  import org.junit.*;
  import org.mockito.InOrder;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.core.Observable;
  import io.reactivex.rxjava3.core.Observer;
  import io.reactivex.rxjava3.disposables.*;
  import io.reactivex.rxjava3.exceptions.TestException;
  import io.reactivex.rxjava3.functions.*;
  import io.reactivex.rxjava3.internal.functions.Functions;
  import io.reactivex.rxjava3.observers.TestObserver;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  import io.reactivex.rxjava3.schedulers.*;
  import io.reactivex.rxjava3.subjects.PublishSubject;
  import io.reactivex.rxjava3.testsupport.*;
  
  public class ObservableAmbTest extends RxJavaTest {
  
      private TestScheduler scheduler;
      private Scheduler.Worker innerScheduler;
  
      @Before
      public void setUp() {
          scheduler = new TestScheduler();
          innerScheduler = scheduler.createWorker();
      }
  
      private Observable<String> createObservable(final String[] values,
              final long interval, final Throwable e) {
          return Observable.unsafeCreate(new ObservableSource<String>() {
  
              @Override
              public void subscribe(final Observer<? super String> observer) {
                  CompositeDisposable parentSubscription = new CompositeDisposable();
  
                  observer.onSubscribe(parentSubscription);
  
                  long delay = interval;
                  for (final String value : values) {
                      parentSubscription.add(innerScheduler.schedule(new Runnable() {
                          @Override
                          public void run() {
                              observer.onNext(value);
                          }
                      }
                      , delay, TimeUnit.MILLISECONDS));
                      delay += interval;
                  }
                  parentSubscription.add(innerScheduler.schedule(new Runnable() {
                      @Override
                      public void run() {
                              if (e == null) {
                                  observer.onComplete();
                              } else {
                                  observer.onError(e);
                              }
                      }
                  }, delay, TimeUnit.MILLISECONDS));
              }
          });
      }
  
      @Test
      public void amb() {
          Observable<String> observable1 = createObservable(new String[] {
                  "1", "11", "111", "1111" }, 2000, null);
          Observable<String> observable2 = createObservable(new String[] {
                  "2", "22", "222", "2222" }, 1000, null);
          Observable<String> observable3 = createObservable(new String[] {
                  "3", "33", "333", "3333" }, 3000, null);
  
          Observable<String> o = Observable.ambArray(observable1,
                  observable2, observable3);
  
          Observer<String> observer = TestHelper.mockObserver();
          o.subscribe(observer);
  
          scheduler.advanceTimeBy(100000, TimeUnit.MILLISECONDS);
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer, times(1)).onNext("2");
          inOrder.verify(observer, times(1)).onNext("22");
          inOrder.verify(observer, times(1)).onNext("222");
          inOrder.verify(observer, times(1)).onNext("2222");
          inOrder.verify(observer, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void amb2() {
          IOException expectedException = new IOException(
                  "fake exception");
          Observable<String> observable1 = createObservable(new String[] {},
                  2000, new IOException("fake exception"));
          Observable<String> observable2 = createObservable(new String[] {
                  "2", "22", "222", "2222" }, 1000, expectedException);
          Observable<String> observable3 = createObservable(new String[] {},
                  3000, new IOException("fake exception"));
  
          Observable<String> o = Observable.ambArray(observable1,
                  observable2, observable3);
  
          Observer<String> observer = TestHelper.mockObserver();
          o.subscribe(observer);
  
          scheduler.advanceTimeBy(100000, TimeUnit.MILLISECONDS);
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer, times(1)).onNext("2");
          inOrder.verify(observer, times(1)).onNext("22");
          inOrder.verify(observer, times(1)).onNext("222");
          inOrder.verify(observer, times(1)).onNext("2222");
          inOrder.verify(observer, times(1)).onError(expectedException);
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void amb3() {
          Observable<String> observable1 = createObservable(new String[] {
                  "1" }, 2000, null);
          Observable<String> observable2 = createObservable(new String[] {},
                  1000, null);
          Observable<String> observable3 = createObservable(new String[] {
                  "3" }, 3000, null);
  
          Observable<String> o = Observable.ambArray(observable1,
                  observable2, observable3);
  
          Observer<String> observer = TestHelper.mockObserver();
          o.subscribe(observer);
  
          scheduler.advanceTimeBy(100000, TimeUnit.MILLISECONDS);
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void subscriptionOnlyHappensOnce() throws InterruptedException {
          final AtomicLong count = new AtomicLong();
          Consumer<Disposable> incrementer = new Consumer<Disposable>() {
              @Override
              public void accept(Disposable d) {
                  count.incrementAndGet();
              }
          };
  
          //this aync stream should emit first
          Observable<Integer> o1 = Observable.just(1).doOnSubscribe(incrementer)
                  .delay(100, TimeUnit.MILLISECONDS).subscribeOn(Schedulers.computation());
          //this stream emits second
          Observable<Integer> o2 = Observable.just(1).doOnSubscribe(incrementer)
                  .delay(100, TimeUnit.MILLISECONDS).subscribeOn(Schedulers.computation());
          TestObserver<Integer> to = new TestObserver<>();
          Observable.ambArray(o1, o2).subscribe(to);
          to.awaitDone(5, TimeUnit.SECONDS);
          to.assertNoErrors();
          assertEquals(2, count.get());
      }
  
      @Test
      public void synchronousSources() {
          // under async subscription the second Observable would complete before
          // the first but because this is a synchronous subscription to sources
          // then second Observable does not get subscribed to before first
          // subscription completes hence first Observable emits result through
          // amb
          int result = Observable.just(1).doOnNext(new Consumer<Integer>() {
              @Override
              public void accept(Integer t) {
                      try {
                          Thread.sleep(100);
                      } catch (InterruptedException e) {
                          //
                      }
              }
          }).ambWith(Observable.just(2)).blockingSingle();
          assertEquals(1, result);
      }
  
      @Test
      public void ambCancelsOthers() {
          PublishSubject<Integer> source1 = PublishSubject.create();
          PublishSubject<Integer> source2 = PublishSubject.create();
          PublishSubject<Integer> source3 = PublishSubject.create();
  
          TestObserver<Integer> to = new TestObserver<>();
  
          Observable.ambArray(source1, source2, source3).subscribe(to);
  
          assertTrue("Source 1 doesn't have subscribers!", source1.hasObservers());
          assertTrue("Source 2 doesn't have subscribers!", source2.hasObservers());
          assertTrue("Source 3 doesn't have subscribers!", source3.hasObservers());
  
          source1.onNext(1);
  
          assertTrue("Source 1 doesn't have subscribers!", source1.hasObservers());
          assertFalse("Source 2 still has subscribers!", source2.hasObservers());
          assertFalse("Source 2 still has subscribers!", source3.hasObservers());
  
      }
  
      @Test
      public void ambArrayEmpty() {
          assertSame(Observable.empty(), Observable.ambArray());
      }
  
      @Test
      public void ambArraySingleElement() {
          assertSame(Observable.never(), Observable.ambArray(Observable.never()));
      }
  
      @Test
      public void manySources() {
          Observable<?>[] a = new Observable[32];
          Arrays.fill(a, Observable.never());
          a[31] = Observable.just(1);
  
          Observable.amb(Arrays.asList(a))
          .test()
          .assertResult(1);
      }
  
      @Test
      public void emptyIterable() {
          Observable.amb(Collections.<Observable<Integer>>emptyList())
          .test()
          .assertResult();
      }
  
      @Test
      public void singleIterable() {
          Observable.amb(Collections.singletonList(Observable.just(1)))
          .test()
          .assertResult(1);
      }
  
      @Test
      public void disposed() {
          TestHelper.checkDisposed(Observable.ambArray(Observable.never(), Observable.never()));
      }
  
      @Test
      public void onNextRace() {
          for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
              final PublishSubject<Integer> ps1 = PublishSubject.create();
              final PublishSubject<Integer> ps2 = PublishSubject.create();
  
              TestObserverEx<Integer> to = Observable.ambArray(ps1, ps2).to(TestHelper.<Integer>testConsumer());
  
              Runnable r1 = new Runnable() {
                  @Override
                  public void run() {
                      ps1.onNext(1);
                  }
              };
              Runnable r2 = new Runnable() {
                  @Override
                  public void run() {
                      ps2.onNext(1);
                  }
              };
  
              TestHelper.race(r1, r2);
  
              to.assertSubscribed()
              .assertNoErrors()
              .assertNotComplete()
              .assertValueCount(1);
          }
      }
  
      @Test
      public void onCompleteRace() {
          for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
              final PublishSubject<Integer> ps1 = PublishSubject.create();
              final PublishSubject<Integer> ps2 = PublishSubject.create();
  
              TestObserver<Integer> to = Observable.ambArray(ps1, ps2).test();
  
              Runnable r1 = new Runnable() {
                  @Override
                  public void run() {
                      ps1.onComplete();
                  }
              };
              Runnable r2 = new Runnable() {
                  @Override
                  public void run() {
                      ps2.onComplete();
                  }
              };
  
              TestHelper.race(r1, r2);
  
              to.assertResult();
          }
      }
  
      @Test
      public void onErrorRace() {
          for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
              final PublishSubject<Integer> ps1 = PublishSubject.create();
              final PublishSubject<Integer> ps2 = PublishSubject.create();
  
              TestObserver<Integer> to = Observable.ambArray(ps1, ps2).test();
  
              final Throwable ex = new TestException();
  
              Runnable r1 = new Runnable() {
                  @Override
                  public void run() {
                      ps1.onError(ex);
                  }
              };
              Runnable r2 = new Runnable() {
                  @Override
                  public void run() {
                      ps2.onError(ex);
                  }
              };
  
              List<Throwable> errors = TestHelper.trackPluginErrors();
              try {
                  TestHelper.race(r1, r2);
              } finally {
                  RxJavaPlugins.reset();
              }
  
              to.assertFailure(TestException.class);
              if (!errors.isEmpty()) {
                  TestHelper.assertUndeliverable(errors, 0, TestException.class);
              }
          }
      }
  
      @Test
      public void ambWithOrder() {
          Observable<Integer> error = Observable.error(new RuntimeException());
          Observable.just(1).ambWith(error).test().assertValue(1).assertComplete();
      }
  
      @Test
      public void ambIterableOrder() {
          Observable<Integer> error = Observable.error(new RuntimeException());
          Observable.amb(Arrays.asList(Observable.just(1), error)).test().assertValue(1).assertComplete();
      }
  
      @Test
      public void ambArrayOrder() {
          Observable<Integer> error = Observable.error(new RuntimeException());
          Observable.ambArray(Observable.just(1), error).test().assertValue(1).assertComplete();
      }
  
      @Test
      public void noWinnerSuccessDispose() throws Exception {
          for (int i = 0; i < TestHelper.RACE_LONG_LOOPS; i++) {
              final AtomicBoolean interrupted = new AtomicBoolean();
              final CountDownLatch cdl = new CountDownLatch(1);
  
              Observable.ambArray(
                  Observable.just(1)
                      .subscribeOn(Schedulers.single())
                      .observeOn(Schedulers.computation()),
                  Observable.never()
              )
              .subscribe(new Consumer<Object>() {
                  @Override
                  public void accept(Object v) throws Exception {
                      interrupted.set(Thread.currentThread().isInterrupted());
                      cdl.countDown();
                  }
              });
  
              assertTrue(cdl.await(500, TimeUnit.SECONDS));
              assertFalse("Interrupted!", interrupted.get());
          }
      }
  
      @Test
      public void noWinnerErrorDispose() throws Exception {
          final TestException ex = new TestException();
          for (int i = 0; i < TestHelper.RACE_LONG_LOOPS; i++) {
              final AtomicBoolean interrupted = new AtomicBoolean();
              final CountDownLatch cdl = new CountDownLatch(1);
  
              Observable.ambArray(
                  Observable.error(ex)
                      .subscribeOn(Schedulers.single())
                      .observeOn(Schedulers.computation()),
                  Observable.never()
              )
              .subscribe(Functions.emptyConsumer(), new Consumer<Throwable>() {
                  @Override
                  public void accept(Throwable e) throws Exception {
                      interrupted.set(Thread.currentThread().isInterrupted());
                      cdl.countDown();
                  }
              });
  
              assertTrue(cdl.await(500, TimeUnit.SECONDS));
              assertFalse("Interrupted!", interrupted.get());
          }
      }
  
      @Test
      public void noWinnerCompleteDispose() throws Exception {
          for (int i = 0; i < TestHelper.RACE_LONG_LOOPS; i++) {
              final AtomicBoolean interrupted = new AtomicBoolean();
              final CountDownLatch cdl = new CountDownLatch(1);
  
              Observable.ambArray(
                  Observable.empty()
                      .subscribeOn(Schedulers.single())
                      .observeOn(Schedulers.computation()),
                  Observable.never()
              )
              .subscribe(Functions.emptyConsumer(), Functions.emptyConsumer(), new Action() {
                  @Override
                  public void run() throws Exception {
                      interrupted.set(Thread.currentThread().isInterrupted());
                      cdl.countDown();
                  }
              });
  
              assertTrue(cdl.await(500, TimeUnit.SECONDS));
              assertFalse("Interrupted!", interrupted.get());
          }
      }
  
      @Test
      public void observableSourcesInIterable() {
          ObservableSource<Integer> source = new ObservableSource<Integer>() {
              @Override
              public void subscribe(Observer<? super Integer> observer) {
                  Observable.just(1).subscribe(observer);
              }
          };
  
          Observable.amb(Arrays.asList(source, source))
          .test()
          .assertResult(1);
      }
  }
  