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.flowable;
  
  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 org.reactivestreams.*;
  
  import io.reactivex.rxjava3.annotations.NonNull;
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.CompositeDisposable;
  import io.reactivex.rxjava3.exceptions.TestException;
  import io.reactivex.rxjava3.functions.*;
  import io.reactivex.rxjava3.internal.functions.Functions;
  import io.reactivex.rxjava3.internal.util.CrashingMappedIterable;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  import io.reactivex.rxjava3.processors.PublishProcessor;
  import io.reactivex.rxjava3.schedulers.*;
  import io.reactivex.rxjava3.subscribers.TestSubscriber;
  import io.reactivex.rxjava3.testsupport.*;
  
  public class FlowableAmbTest extends RxJavaTest {
  
      private TestScheduler scheduler;
      private Scheduler.Worker innerScheduler;
  
      @Before
      public void setUp() {
          scheduler = new TestScheduler();
          innerScheduler = scheduler.createWorker();
      }
  
      private Flowable<String> createFlowable(final String[] values,
              final long interval, final Throwable e) {
          return Flowable.unsafeCreate(new Publisher<String>() {
  
              @Override
              public void subscribe(final Subscriber<? super String> subscriber) {
                  final CompositeDisposable parentSubscription = new CompositeDisposable();
  
                  subscriber.onSubscribe(new Subscription() {
                      @Override
                      public void request(long n) {
  
                      }
  
                      @Override
                      public void cancel() {
                          parentSubscription.dispose();
                      }
                  });
  
                  long delay = interval;
                  for (final String value : values) {
                      parentSubscription.add(innerScheduler.schedule(new Runnable() {
                          @Override
                          public void run() {
                              subscriber.onNext(value);
                          }
                      }
                      , delay, TimeUnit.MILLISECONDS));
                      delay += interval;
                  }
                  parentSubscription.add(innerScheduler.schedule(new Runnable() {
                      @Override
                      public void run() {
                              if (e == null) {
                                  subscriber.onComplete();
                              } else {
                                  subscriber.onError(e);
                              }
                      }
                  }, delay, TimeUnit.MILLISECONDS));
              }
          });
      }
  
      @Test
      public void amb() {
          Flowable<String> flowable1 = createFlowable(new String[] {
                  "1", "11", "111", "1111" }, 2000, null);
          Flowable<String> flowable2 = createFlowable(new String[] {
                  "2", "22", "222", "2222" }, 1000, null);
          Flowable<String> flowable3 = createFlowable(new String[] {
                  "3", "33", "333", "3333" }, 3000, null);
  
          Flowable<String> f = Flowable.ambArray(flowable1,
                  flowable2, flowable3);
  
          Subscriber<String> subscriber = TestHelper.mockSubscriber();
          f.subscribe(subscriber);
  
          scheduler.advanceTimeBy(100000, TimeUnit.MILLISECONDS);
  
          InOrder inOrder = inOrder(subscriber);
          inOrder.verify(subscriber, times(1)).onNext("2");
          inOrder.verify(subscriber, times(1)).onNext("22");
          inOrder.verify(subscriber, times(1)).onNext("222");
          inOrder.verify(subscriber, times(1)).onNext("2222");
          inOrder.verify(subscriber, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void amb2() {
          IOException expectedException = new IOException(
                  "fake exception");
          Flowable<String> flowable1 = createFlowable(new String[] {},
                  2000, new IOException("fake exception"));
          Flowable<String> flowable2 = createFlowable(new String[] {
                  "2", "22", "222", "2222" }, 1000, expectedException);
          Flowable<String> flowable3 = createFlowable(new String[] {},
                  3000, new IOException("fake exception"));
  
          Flowable<String> f = Flowable.ambArray(flowable1,
                  flowable2, flowable3);
  
          Subscriber<String> subscriber = TestHelper.mockSubscriber();
          f.subscribe(subscriber);
  
          scheduler.advanceTimeBy(100000, TimeUnit.MILLISECONDS);
  
          InOrder inOrder = inOrder(subscriber);
          inOrder.verify(subscriber, times(1)).onNext("2");
          inOrder.verify(subscriber, times(1)).onNext("22");
          inOrder.verify(subscriber, times(1)).onNext("222");
          inOrder.verify(subscriber, times(1)).onNext("2222");
          inOrder.verify(subscriber, times(1)).onError(expectedException);
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void amb3() {
          Flowable<String> flowable1 = createFlowable(new String[] {
                  "1" }, 2000, null);
          Flowable<String> flowable2 = createFlowable(new String[] {},
                  1000, null);
          Flowable<String> flowable3 = createFlowable(new String[] {
                  "3" }, 3000, null);
  
          Flowable<String> f = Flowable.ambArray(flowable1,
                  flowable2, flowable3);
  
          Subscriber<String> subscriber = TestHelper.mockSubscriber();
          f.subscribe(subscriber);
  
          scheduler.advanceTimeBy(100000, TimeUnit.MILLISECONDS);
          InOrder inOrder = inOrder(subscriber);
          inOrder.verify(subscriber, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void producerRequestThroughAmb() {
          TestSubscriber<Integer> ts = new TestSubscriber<>(0L);
          ts.request(3);
          final AtomicLong requested1 = new AtomicLong();
          final AtomicLong requested2 = new AtomicLong();
          Flowable<Integer> f1 = Flowable.unsafeCreate(new Publisher<Integer>() {
  
              @Override
              public void subscribe(Subscriber<? super Integer> s) {
                  s.onSubscribe(new Subscription() {
  
                      @Override
                      public void request(long n) {
                          System.out.println("1-requested: " + n);
                          requested1.set(n);
                      }
  
                      @Override
                      public void cancel() {
  
                      }
                  });
              }
  
          });
          Flowable<Integer> f2 = Flowable.unsafeCreate(new Publisher<Integer>() {
  
              @Override
              public void subscribe(Subscriber<? super Integer> s) {
                  s.onSubscribe(new Subscription() {
  
                      @Override
                      public void request(long n) {
                          System.out.println("2-requested: " + n);
                          requested2.set(n);
                      }
  
                      @Override
                      public void cancel() {
  
                      }
                  });
              }
  
          });
          Flowable.ambArray(f1, f2).subscribe(ts);
          assertEquals(3, requested1.get());
          assertEquals(3, requested2.get());
      }
  
      @Test
      public void backpressure() {
          TestSubscriber<Integer> ts = new TestSubscriber<>();
          Flowable.range(0, Flowable.bufferSize() * 2)
                  .ambWith(Flowable.range(0, Flowable.bufferSize() * 2))
                  .observeOn(Schedulers.computation()) // observeOn has a backpressured RxRingBuffer
                  .delay(1, TimeUnit.MICROSECONDS) // make it a slightly slow consumer
                  .subscribe(ts);
  
          ts.awaitDone(5, TimeUnit.SECONDS);
          ts.assertNoErrors();
          assertEquals(Flowable.bufferSize() * 2, ts.values().size());
      }
  
      @Test
      public void subscriptionOnlyHappensOnce() throws InterruptedException {
          final AtomicLong count = new AtomicLong();
          Consumer<Subscription> incrementer = new Consumer<Subscription>() {
              @Override
              public void accept(Subscription s) {
                  count.incrementAndGet();
              }
          };
  
          //this aync stream should emit first
          Flowable<Integer> f1 = Flowable.just(1).doOnSubscribe(incrementer)
                  .delay(100, TimeUnit.MILLISECONDS).subscribeOn(Schedulers.computation());
          //this stream emits second
          Flowable<Integer> f2 = Flowable.just(1).doOnSubscribe(incrementer)
                  .delay(100, TimeUnit.MILLISECONDS).subscribeOn(Schedulers.computation());
          TestSubscriber<Integer> ts = new TestSubscriber<>();
          Flowable.ambArray(f1, f2).subscribe(ts);
          ts.request(1);
          ts.awaitDone(5, TimeUnit.SECONDS);
          ts.assertNoErrors();
          assertEquals(2, count.get());
      }
  
      @Test
      public void secondaryRequestsPropagatedToChildren() throws InterruptedException {
          //this aync stream should emit first
          Flowable<Integer> f1 = Flowable.fromArray(1, 2, 3)
                  .delay(100, TimeUnit.MILLISECONDS).subscribeOn(Schedulers.computation());
          //this stream emits second
          Flowable<Integer> f2 = Flowable.fromArray(4, 5, 6)
                  .delay(200, TimeUnit.MILLISECONDS).subscribeOn(Schedulers.computation());
          TestSubscriber<Integer> ts = new TestSubscriber<>(1L);
  
          Flowable.ambArray(f1, f2).subscribe(ts);
          // before first emission request 20 more
          // this request should suffice to emit all
          ts.request(20);
          //ensure stream does not hang
          ts.awaitDone(5, TimeUnit.SECONDS);
          ts.assertNoErrors();
      }
  
      @Test
      public void synchronousSources() {
          // under async subscription the second Flowable would complete before
          // the first but because this is a synchronous subscription to sources
          // then second Flowable does not get subscribed to before first
          // subscription completes hence first Flowable emits result through
          // amb
          int result = Flowable.just(1).doOnNext(new Consumer<Integer>() {
              @Override
              public void accept(Integer t) {
                      try {
                          Thread.sleep(100);
                      } catch (InterruptedException e) {
                          //
                      }
              }
          }).ambWith(Flowable.just(2)).blockingSingle();
          assertEquals(1, result);
      }
  
      @Test
      public void ambCancelsOthers() {
          PublishProcessor<Integer> source1 = PublishProcessor.create();
          PublishProcessor<Integer> source2 = PublishProcessor.create();
          PublishProcessor<Integer> source3 = PublishProcessor.create();
  
          TestSubscriber<Integer> ts = new TestSubscriber<>();
  
          Flowable.ambArray(source1, source2, source3).subscribe(ts);
  
          assertTrue("Source 1 doesn't have subscribers!", source1.hasSubscribers());
          assertTrue("Source 2 doesn't have subscribers!", source2.hasSubscribers());
          assertTrue("Source 3 doesn't have subscribers!", source3.hasSubscribers());
  
          source1.onNext(1);
  
          assertTrue("Source 1 doesn't have subscribers!", source1.hasSubscribers());
          assertFalse("Source 2 still has subscribers!", source2.hasSubscribers());
          assertFalse("Source 2 still has subscribers!", source3.hasSubscribers());
  
      }
  
      @Test
      public void multipleUse() {
          TestSubscriber<Long> ts1 = new TestSubscriber<>();
          TestSubscriber<Long> ts2 = new TestSubscriber<>();
  
          Flowable<Long> amb = Flowable.timer(100, TimeUnit.MILLISECONDS).ambWith(Flowable.timer(200, TimeUnit.MILLISECONDS));
  
          amb.subscribe(ts1);
          amb.subscribe(ts2);
  
          ts1.awaitDone(5, TimeUnit.SECONDS);
          ts2.awaitDone(5, TimeUnit.SECONDS);
  
          ts1.assertValue(0L);
          ts1.assertComplete();
          ts1.assertNoErrors();
  
          ts2.assertValue(0L);
          ts2.assertComplete();
          ts2.assertNoErrors();
      }
  
      @Test
      public void ambIterable() {
          PublishProcessor<Integer> pp1 = PublishProcessor.create();
          PublishProcessor<Integer> pp2 = PublishProcessor.create();
  
          TestSubscriber<Integer> ts = TestSubscriber.create();
  
          Flowable.amb(Arrays.asList(pp1, pp2)).subscribe(ts);
  
          ts.assertNoValues();
  
          pp1.onNext(1);
          pp1.onComplete();
  
          assertFalse(pp1.hasSubscribers());
          assertFalse(pp2.hasSubscribers());
  
          ts.assertValue(1);
          ts.assertNoErrors();
          ts.assertComplete();
      }
  
      @Test
      public void ambIterable2() {
          PublishProcessor<Integer> pp1 = PublishProcessor.create();
          PublishProcessor<Integer> pp2 = PublishProcessor.create();
  
          TestSubscriber<Integer> ts = TestSubscriber.create();
  
          Flowable.amb(Arrays.asList(pp1, pp2)).subscribe(ts);
  
          ts.assertNoValues();
  
          pp2.onNext(2);
          pp2.onComplete();
  
          assertFalse(pp1.hasSubscribers());
          assertFalse(pp2.hasSubscribers());
  
          ts.assertValue(2);
          ts.assertNoErrors();
          ts.assertComplete();
      }
  
      @Test
      public void ambArrayEmpty() {
          assertSame(Flowable.empty(), Flowable.ambArray());
      }
  
      @Test
      public void ambArraySingleElement() {
          assertSame(Flowable.never(), Flowable.ambArray(Flowable.never()));
      }
  
      @Test
      public void disposed() {
          TestHelper.checkDisposed(Flowable.ambArray(Flowable.never(), Flowable.never()));
      }
  
      @Test
      public void manySources() {
          Flowable<?>[] a = new Flowable[32];
          Arrays.fill(a, Flowable.never());
          a[31] = Flowable.just(1);
  
          Flowable.amb(Arrays.asList(a))
          .test()
          .assertResult(1);
      }
  
      @Test
      public void emptyIterable() {
          Flowable.amb(Collections.<Flowable<Integer>>emptyList())
          .test()
          .assertResult();
      }
  
      @Test
      public void singleIterable() {
          Flowable.amb(Collections.singletonList(Flowable.just(1)))
          .test()
          .assertResult(1);
      }
  
      @Test
      public void onNextRace() {
          for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
              final PublishProcessor<Integer> pp1 = PublishProcessor.create();
              final PublishProcessor<Integer> pp2 = PublishProcessor.create();
  
              TestSubscriberEx<Integer> ts = Flowable.ambArray(pp1, pp2).to(TestHelper.<Integer>testConsumer());
  
              Runnable r1 = new Runnable() {
                  @Override
                  public void run() {
                      pp1.onNext(1);
                  }
              };
              Runnable r2 = new Runnable() {
                  @Override
                  public void run() {
                      pp2.onNext(1);
                  }
              };
  
              TestHelper.race(r1, r2);
  
              ts.assertSubscribed().assertNoErrors()
              .assertNotComplete().assertValueCount(1);
          }
      }
  
      @Test
      public void onCompleteRace() {
          for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
              final PublishProcessor<Integer> pp1 = PublishProcessor.create();
              final PublishProcessor<Integer> pp2 = PublishProcessor.create();
  
              TestSubscriber<Integer> ts = Flowable.ambArray(pp1, pp2).test();
  
              Runnable r1 = new Runnable() {
                  @Override
                  public void run() {
                      pp1.onComplete();
                  }
              };
              Runnable r2 = new Runnable() {
                  @Override
                  public void run() {
                      pp2.onComplete();
                  }
              };
  
              TestHelper.race(r1, r2);
  
              ts.assertResult();
          }
      }
  
      @Test
      public void onErrorRace() {
          for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
              final PublishProcessor<Integer> pp1 = PublishProcessor.create();
              final PublishProcessor<Integer> pp2 = PublishProcessor.create();
  
              TestSubscriber<Integer> ts = Flowable.ambArray(pp1, pp2).test();
  
              final Throwable ex = new TestException();
  
              Runnable r1 = new Runnable() {
                  @Override
                  public void run() {
                      pp1.onError(ex);
                  }
              };
              Runnable r2 = new Runnable() {
                  @Override
                  public void run() {
                      pp2.onError(ex);
                  }
              };
  
              List<Throwable> errors = TestHelper.trackPluginErrors();
              try {
                  TestHelper.race(r1, r2);
              } finally {
                  RxJavaPlugins.reset();
              }
  
              ts.assertFailure(TestException.class);
              if (!errors.isEmpty()) {
                  TestHelper.assertUndeliverable(errors, 0, TestException.class);
              }
          }
      }
  
      @Test
      public void nullIterableElement() {
          Flowable.amb(Arrays.asList(Flowable.never(), null, Flowable.never()))
          .test()
          .assertFailure(NullPointerException.class);
      }
  
      @Test
      public void iteratorThrows() {
          Flowable.amb(new CrashingMappedIterable<>(1, 100, 100, new Function<Integer, Flowable<Integer>>() {
              @Override
              public Flowable<Integer> apply(Integer v) throws Exception {
                  return Flowable.never();
              }
          }))
          .to(TestHelper.<Integer>testConsumer())
          .assertFailureAndMessage(TestException.class, "iterator()");
  
          Flowable.amb(new CrashingMappedIterable<>(100, 1, 100, new Function<Integer, Flowable<Integer>>() {
              @Override
              public Flowable<Integer> apply(Integer v) throws Exception {
                  return Flowable.never();
              }
          }))
          .to(TestHelper.<Integer>testConsumer())
          .assertFailureAndMessage(TestException.class, "hasNext()");
  
          Flowable.amb(new CrashingMappedIterable<>(100, 100, 1, new Function<Integer, Flowable<Integer>>() {
              @Override
              public Flowable<Integer> apply(Integer v) throws Exception {
                  return Flowable.never();
              }
          }))
          .to(TestHelper.<Integer>testConsumer())
          .assertFailureAndMessage(TestException.class, "next()");
      }
  
      @Test
      public void ambWithOrder() {
          Flowable<Integer> error = Flowable.error(new RuntimeException());
          Flowable.just(1).ambWith(error).test().assertValue(1).assertComplete();
      }
  
      @Test
      public void ambIterableOrder() {
          Flowable<Integer> error = Flowable.error(new RuntimeException());
          Flowable.amb(Arrays.asList(Flowable.just(1), error)).test().assertValue(1).assertComplete();
      }
  
      @Test
      public void ambArrayOrder() {
          Flowable<Integer> error = Flowable.error(new RuntimeException());
          Flowable.ambArray(Flowable.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);
  
              Flowable.ambArray(
                  Flowable.just(1)
                      .subscribeOn(Schedulers.single())
                      .observeOn(Schedulers.computation()),
                  Flowable.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);
  
              Flowable.ambArray(
                  Flowable.error(ex)
                      .subscribeOn(Schedulers.single())
                      .observeOn(Schedulers.computation()),
                  Flowable.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);
  
              Flowable.ambArray(
                  Flowable.empty()
                      .subscribeOn(Schedulers.single())
                      .observeOn(Schedulers.computation()),
                  Flowable.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 publishersInIterable() {
          Publisher<Integer> source = new Publisher<Integer>() {
              @Override
              public void subscribe(Subscriber<? super Integer> subscriber) {
                  Flowable.just(1).subscribe(subscriber);
              }
          };
  
          Flowable.amb(Arrays.asList(source, source))
          .test()
          .assertResult(1);
      }
  
      @Test
      public void badRequest() {
          TestHelper.assertBadRequestReported(Flowable.amb(Arrays.asList(Flowable.never(), Flowable.never())));
      }
  
      @Test
      public void requestAfterCancel() {
          Flowable.amb(Arrays.asList(Flowable.never(), Flowable.never()))
          .subscribe(new FlowableSubscriber<Object>() {
  
              @Override
              public void onNext(@NonNull Object t) {
              }
  
              @Override
              public void onError(Throwable t) {
              }
  
              @Override
              public void onComplete() {
              }
  
              @Override
              public void onSubscribe(@NonNull Subscription s) {
                  s.cancel();
                  s.request(1);
              }
          });
      }
  }
  