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.ArgumentMatchers.*;
  import static org.mockito.Mockito.*;
  
  import java.util.List;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicReference;
  
  import io.reactivex.rxjava3.functions.Action;
  import org.junit.*;
  import org.mockito.InOrder;
  import org.reactivestreams.*;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.exceptions.*;
  import io.reactivex.rxjava3.functions.Function;
  import io.reactivex.rxjava3.internal.functions.Functions;
  import io.reactivex.rxjava3.internal.operators.flowable.FlowableDebounceTimed.*;
  import io.reactivex.rxjava3.internal.subscriptions.BooleanSubscription;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  import io.reactivex.rxjava3.processors.*;
  import io.reactivex.rxjava3.schedulers.TestScheduler;
  import io.reactivex.rxjava3.subscribers.TestSubscriber;
  import io.reactivex.rxjava3.testsupport.*;
  
  public class FlowableDebounceTest extends RxJavaTest {
  
      private TestScheduler scheduler;
      private Subscriber<String> subscriber;
      private Scheduler.Worker innerScheduler;
  
      @Before
      public void before() {
          scheduler = new TestScheduler();
          subscriber = TestHelper.mockSubscriber();
          innerScheduler = scheduler.createWorker();
      }
  
      @Test
      public void debounceWithOnDroppedCallbackWithEx() throws Throwable {
          Flowable<String> source = Flowable.unsafeCreate(new Publisher<String>() {
              @Override
              public void subscribe(Subscriber<? super String> subscriber) {
                  subscriber.onSubscribe(new BooleanSubscription());
                  publishNext(subscriber, 100, "one");    // Should be skipped since "two" will arrive before the timeout expires.
                  publishNext(subscriber, 400, "two");    // Should be published since "three" will arrive after the timeout expires.
                  publishNext(subscriber, 900, "three");   // Should be skipped since "four" will arrive before the timout expires.
                  publishNext(subscriber, 999, "four");   // Should be skipped since onComplete will arrive before the timeout expires.
                  publishCompleted(subscriber, 1000);     // Should be published as soon as the timeout expires.
              }
          });
  
          Action whenDisposed = mock(Action.class);
  
          Flowable<String> sampled = source
                  .doOnCancel(whenDisposed)
                  .debounce(400, TimeUnit.MILLISECONDS, scheduler, e ->  {
                      if ("three".equals(e)) {
                          throw new TestException("forced");
                      }
                  });
          sampled.subscribe(subscriber);
  
          InOrder inOrder = inOrder(subscriber);
  
          scheduler.advanceTimeTo(1000, TimeUnit.MILLISECONDS);
          inOrder.verify(subscriber, times(1)).onNext("two");
          inOrder.verify(subscriber, times(1)).onError(any(TestException.class));
          inOrder.verify(subscriber, times(0)).onNext("three");
          inOrder.verify(subscriber, times(0)).onNext("four");
          inOrder.verify(subscriber, times(0)).onComplete();
          inOrder.verifyNoMoreInteractions();
          verify(whenDisposed).run();
      }
  
      @Test
      public void debounceWithOnDroppedCallback() {
          Flowable<String> source = Flowable.unsafeCreate(new Publisher<String>() {
              @Override
              public void subscribe(Subscriber<? super String> subscriber) {
                  subscriber.onSubscribe(new BooleanSubscription());
                  publishNext(subscriber, 100, "one");    // Should be skipped since "two" will arrive before the timeout expires.
                  publishNext(subscriber, 400, "two");    // Should be published since "three" will arrive after the timeout expires.
                  publishNext(subscriber, 900, "three");   // Should be skipped since "four" will arrive before the timout expires.
                  publishNext(subscriber, 999, "four");   // Should be skipped since onComplete will arrive before the timeout expires.
                  publishCompleted(subscriber, 1000);     // Should be published as soon as the timeout expires.
              }
          });
  
          Observer<Object> dropCallbackObserver = TestHelper.mockObserver();
          Flowable<String> sampled = source.debounce(400, TimeUnit.MILLISECONDS, scheduler, dropCallbackObserver::onNext);
          sampled.subscribe(subscriber);
  
          scheduler.advanceTimeTo(0, TimeUnit.MILLISECONDS);
          InOrder inOrder = inOrder(subscriber);
          InOrder dropCallbackOrder = inOrder(dropCallbackObserver);
  
          // must go to 800 since it must be 400 after when two is sent, which is at 400
          scheduler.advanceTimeTo(800, TimeUnit.MILLISECONDS);
          inOrder.verify(subscriber, times(1)).onNext("two");
          dropCallbackOrder.verify(dropCallbackObserver, times(1)).onNext("one");
          scheduler.advanceTimeTo(1000, TimeUnit.MILLISECONDS);
          dropCallbackOrder.verify(dropCallbackObserver, times(1)).onNext("three");
          inOrder.verify(subscriber, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
          dropCallbackOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void debounceWithCompleted() {
          Flowable<String> source = Flowable.unsafeCreate(new Publisher<String>() {
              @Override
              public void subscribe(Subscriber<? super String> subscriber) {
                  subscriber.onSubscribe(new BooleanSubscription());
                  publishNext(subscriber, 100, "one");    // Should be skipped since "two" will arrive before the timeout expires.
                  publishNext(subscriber, 400, "two");    // Should be published since "three" will arrive after the timeout expires.
                  publishNext(subscriber, 900, "three");   // Should be skipped since onComplete will arrive before the timeout expires.
                  publishCompleted(subscriber, 1000);     // Should be published as soon as the timeout expires.
              }
          });
  
          Flowable<String> sampled = source.debounce(400, TimeUnit.MILLISECONDS, scheduler);
          sampled.subscribe(subscriber);
  
          scheduler.advanceTimeTo(0, TimeUnit.MILLISECONDS);
          InOrder inOrder = inOrder(subscriber);
          // must go to 800 since it must be 400 after when two is sent, which is at 400
          scheduler.advanceTimeTo(800, TimeUnit.MILLISECONDS);
          inOrder.verify(subscriber, times(1)).onNext("two");
          scheduler.advanceTimeTo(1000, TimeUnit.MILLISECONDS);
          inOrder.verify(subscriber, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void debounceNeverEmits() {
          Flowable<String> source = Flowable.unsafeCreate(new Publisher<String>() {
              @Override
              public void subscribe(Subscriber<? super String> subscriber) {
                  subscriber.onSubscribe(new BooleanSubscription());
                  // all should be skipped since they are happening faster than the 200ms timeout
                  publishNext(subscriber, 100, "a");    // Should be skipped
                  publishNext(subscriber, 200, "b");    // Should be skipped
                  publishNext(subscriber, 300, "c");    // Should be skipped
                  publishNext(subscriber, 400, "d");    // Should be skipped
                  publishNext(subscriber, 500, "e");    // Should be skipped
                  publishNext(subscriber, 600, "f");    // Should be skipped
                  publishNext(subscriber, 700, "g");    // Should be skipped
                  publishNext(subscriber, 800, "h");    // Should be skipped
                  publishCompleted(subscriber, 900);     // Should be published as soon as the timeout expires.
              }
          });
  
          Flowable<String> sampled = source.debounce(200, TimeUnit.MILLISECONDS, scheduler);
          sampled.subscribe(subscriber);
  
          scheduler.advanceTimeTo(0, TimeUnit.MILLISECONDS);
          InOrder inOrder = inOrder(subscriber);
          inOrder.verify(subscriber, times(0)).onNext(anyString());
          scheduler.advanceTimeTo(1000, TimeUnit.MILLISECONDS);
          inOrder.verify(subscriber, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void debounceWithError() {
          Flowable<String> source = Flowable.unsafeCreate(new Publisher<String>() {
              @Override
              public void subscribe(Subscriber<? super String> subscriber) {
                  subscriber.onSubscribe(new BooleanSubscription());
                  Exception error = new TestException();
                  publishNext(subscriber, 100, "one");    // Should be published since "two" will arrive after the timeout expires.
                  publishNext(subscriber, 600, "two");    // Should be skipped since onError will arrive before the timeout expires.
                  publishError(subscriber, 700, error);   // Should be published as soon as the timeout expires.
              }
          });
  
          Flowable<String> sampled = source.debounce(400, TimeUnit.MILLISECONDS, scheduler);
          sampled.subscribe(subscriber);
  
          scheduler.advanceTimeTo(0, TimeUnit.MILLISECONDS);
          InOrder inOrder = inOrder(subscriber);
          // 100 + 400 means it triggers at 500
          scheduler.advanceTimeTo(500, TimeUnit.MILLISECONDS);
          inOrder.verify(subscriber).onNext("one");
          scheduler.advanceTimeTo(701, TimeUnit.MILLISECONDS);
          inOrder.verify(subscriber).onError(any(TestException.class));
          inOrder.verifyNoMoreInteractions();
      }
  
      private <T> void publishCompleted(final Subscriber<T> subscriber, long delay) {
          innerScheduler.schedule(new Runnable() {
              @Override
              public void run() {
                  subscriber.onComplete();
              }
          }, delay, TimeUnit.MILLISECONDS);
      }
  
      private <T> void publishError(final Subscriber<T> subscriber, long delay, final Exception error) {
          innerScheduler.schedule(new Runnable() {
              @Override
              public void run() {
                  subscriber.onError(error);
              }
          }, delay, TimeUnit.MILLISECONDS);
      }
  
      private <T> void publishNext(final Subscriber<T> subscriber, final long delay, final T value) {
          innerScheduler.schedule(new Runnable() {
              @Override
              public void run() {
                  subscriber.onNext(value);
              }
          }, delay, TimeUnit.MILLISECONDS);
      }
  
      @Test
      public void debounceSelectorNormal1() {
          PublishProcessor<Integer> source = PublishProcessor.create();
          final PublishProcessor<Integer> debouncer = PublishProcessor.create();
          Function<Integer, Flowable<Integer>> debounceSel = new Function<Integer, Flowable<Integer>>() {
  
              @Override
              public Flowable<Integer> apply(Integer t1) {
                  return debouncer;
              }
          };
  
          Subscriber<Object> subscriber = TestHelper.mockSubscriber();
          InOrder inOrder = inOrder(subscriber);
  
          source.debounce(debounceSel).subscribe(subscriber);
  
          source.onNext(1);
          debouncer.onNext(1);
  
          source.onNext(2);
          source.onNext(3);
          source.onNext(4);
  
          debouncer.onNext(2);
  
          source.onNext(5);
          source.onComplete();
  
          inOrder.verify(subscriber).onNext(1);
          inOrder.verify(subscriber).onNext(4);
          inOrder.verify(subscriber).onNext(5);
          inOrder.verify(subscriber).onComplete();
  
          verify(subscriber, never()).onError(any(Throwable.class));
      }
  
      @Test
      public void debounceSelectorFuncThrows() {
          PublishProcessor<Integer> source = PublishProcessor.create();
          Function<Integer, Flowable<Integer>> debounceSel = new Function<Integer, Flowable<Integer>>() {
  
              @Override
              public Flowable<Integer> apply(Integer t1) {
                  throw new TestException();
              }
          };
  
          Subscriber<Object> subscriber = TestHelper.mockSubscriber();
  
          source.debounce(debounceSel).subscribe(subscriber);
  
          source.onNext(1);
  
          verify(subscriber, never()).onNext(any());
          verify(subscriber, never()).onComplete();
          verify(subscriber).onError(any(TestException.class));
      }
  
      @Test
      public void debounceSelectorFlowableThrows() {
          PublishProcessor<Integer> source = PublishProcessor.create();
          Function<Integer, Flowable<Integer>> debounceSel = new Function<Integer, Flowable<Integer>>() {
  
              @Override
              public Flowable<Integer> apply(Integer t1) {
                  return Flowable.error(new TestException());
              }
          };
  
          Subscriber<Object> subscriber = TestHelper.mockSubscriber();
  
          source.debounce(debounceSel).subscribe(subscriber);
  
          source.onNext(1);
  
          verify(subscriber, never()).onNext(any());
          verify(subscriber, never()).onComplete();
          verify(subscriber).onError(any(TestException.class));
      }
  
      @Test
      public void debounceTimedLastIsNotLost() {
          PublishProcessor<Integer> source = PublishProcessor.create();
  
          Subscriber<Object> subscriber = TestHelper.mockSubscriber();
  
          source.debounce(100, TimeUnit.MILLISECONDS, scheduler).subscribe(subscriber);
  
          source.onNext(1);
          source.onComplete();
  
          scheduler.advanceTimeBy(1, TimeUnit.SECONDS);
  
          verify(subscriber).onNext(1);
          verify(subscriber).onComplete();
          verify(subscriber, never()).onError(any(Throwable.class));
      }
  
      @Test
      public void debounceSelectorLastIsNotLost() {
          PublishProcessor<Integer> source = PublishProcessor.create();
          final PublishProcessor<Integer> debouncer = PublishProcessor.create();
  
          Function<Integer, Flowable<Integer>> debounceSel = new Function<Integer, Flowable<Integer>>() {
  
              @Override
              public Flowable<Integer> apply(Integer t1) {
                  return debouncer;
              }
          };
  
          Subscriber<Object> subscriber = TestHelper.mockSubscriber();
  
          source.debounce(debounceSel).subscribe(subscriber);
  
          source.onNext(1);
          source.onComplete();
  
          debouncer.onComplete();
  
          verify(subscriber).onNext(1);
          verify(subscriber).onComplete();
          verify(subscriber, never()).onError(any(Throwable.class));
      }
  
      @Test
      public void debounceWithTimeBackpressure() throws InterruptedException {
          TestScheduler scheduler = new TestScheduler();
          TestSubscriberEx<Integer> subscriber = new TestSubscriberEx<>();
          Flowable.merge(
                  Flowable.just(1),
                  Flowable.just(2).delay(10, TimeUnit.MILLISECONDS, scheduler)
          ).debounce(20, TimeUnit.MILLISECONDS, scheduler).take(1).subscribe(subscriber);
  
          scheduler.advanceTimeBy(30, TimeUnit.MILLISECONDS);
  
          subscriber.assertValue(2);
          subscriber.assertTerminated();
          subscriber.assertNoErrors();
      }
  
      @Test
      public void debounceDefaultScheduler() throws Exception {
  
          TestSubscriber<Integer> ts = new TestSubscriber<>();
  
          Flowable.range(1, 1000).debounce(1, TimeUnit.SECONDS).subscribe(ts);
  
          ts.awaitDone(5, TimeUnit.SECONDS);
          ts.assertValue(1000);
          ts.assertNoErrors();
          ts.assertComplete();
      }
  
      @Test
      public void debounceDefault() throws Exception {
  
          Flowable.just(1).debounce(1, TimeUnit.SECONDS)
          .test()
          .awaitDone(5, TimeUnit.SECONDS)
          .assertResult(1);
      }
  
      @Test
      public void dispose() {
          TestHelper.checkDisposed(PublishProcessor.create().debounce(1, TimeUnit.SECONDS, new TestScheduler()));
  
          TestHelper.checkDisposed(PublishProcessor.create().debounce(Functions.justFunction(Flowable.never())));
  
          Disposable d = new FlowableDebounceTimed.DebounceEmitter<>(1, 1, null);
          assertFalse(d.isDisposed());
  
          d.dispose();
  
          assertTrue(d.isDisposed());
      }
  
      @Test
      public void badSource() {
          List<Throwable> errors = TestHelper.trackPluginErrors();
          try {
              new Flowable<Integer>() {
                  @Override
                  protected void subscribeActual(Subscriber<? super Integer> subscriber) {
                      subscriber.onSubscribe(new BooleanSubscription());
                      subscriber.onComplete();
                      subscriber.onNext(1);
                      subscriber.onError(new TestException());
                      subscriber.onComplete();
                  }
              }
              .debounce(1, TimeUnit.SECONDS, new TestScheduler())
              .test()
              .assertResult();
  
              TestHelper.assertUndeliverable(errors, 0, TestException.class);
          } finally {
              RxJavaPlugins.reset();
          }
      }
  
      @Test
      public void badSourceSelector() {
          TestHelper.checkBadSourceFlowable(new Function<Flowable<Integer>, Object>() {
              @Override
              public Object apply(Flowable<Integer> f) throws Exception {
                  return f.debounce(new Function<Integer, Flowable<Long>>() {
                      @Override
                      public Flowable<Long> apply(Integer v) throws Exception {
                          return Flowable.timer(1, TimeUnit.SECONDS);
                      }
                  });
              }
          }, false, 1, 1, 1);
  
          TestHelper.checkBadSourceFlowable(new Function<Flowable<Integer>, Object>() {
              @Override
              public Object apply(final Flowable<Integer> f) throws Exception {
                  return Flowable.just(1).debounce(new Function<Integer, Flowable<Integer>>() {
                      @Override
                      public Flowable<Integer> apply(Integer v) throws Exception {
                          return f;
                      }
                  });
              }
          }, false, 1, 1, 1);
      }
  
      @Test
      public void debounceWithEmpty() {
          Flowable.just(1).debounce(Functions.justFunction(Flowable.empty()))
          .test()
          .assertResult(1);
      }
  
      @Test
      public void backpressureNoRequest() {
          Flowable.just(1)
          .debounce(Functions.justFunction(Flowable.timer(1, TimeUnit.MILLISECONDS)))
          .test(0L)
          .awaitDone(5, TimeUnit.SECONDS)
          .assertFailure(MissingBackpressureException.class);
      }
  
      @Test
      public void backpressureNoRequestTimed() {
          Flowable.just(1)
          .debounce(1, TimeUnit.MILLISECONDS)
          .test(0L)
          .awaitDone(5, TimeUnit.SECONDS)
          .assertFailure(MissingBackpressureException.class);
      }
  
      @Test
      public void doubleOnSubscribe() {
          TestHelper.checkDoubleOnSubscribeFlowable(new Function<Flowable<Object>, Flowable<Object>>() {
              @Override
              public Flowable<Object> apply(Flowable<Object> f) throws Exception {
                  return f.debounce(Functions.justFunction(Flowable.never()));
              }
          });
      }
  
      @Test
      public void disposeInOnNext() {
          final TestSubscriber<Integer> ts = new TestSubscriber<>();
  
          BehaviorProcessor.createDefault(1)
          .debounce(new Function<Integer, Flowable<Object>>() {
              @Override
              public Flowable<Object> apply(Integer o) throws Exception {
                  ts.cancel();
                  return Flowable.never();
              }
          })
          .subscribeWith(ts)
          .assertEmpty();
  
          assertTrue(ts.isCancelled());
      }
  
      @Test
      public void disposedInOnComplete() {
          final TestSubscriber<Integer> ts = new TestSubscriber<>();
  
          new Flowable<Integer>() {
              @Override
              protected void subscribeActual(Subscriber<? super Integer> subscriber) {
                  subscriber.onSubscribe(new BooleanSubscription());
                  ts.cancel();
                  subscriber.onComplete();
              }
          }
          .debounce(Functions.justFunction(Flowable.never()))
          .subscribeWith(ts)
          .assertEmpty();
      }
  
      @Test
      public void emitLate() {
          final AtomicReference<Subscriber<? super Integer>> ref = new AtomicReference<>();
  
          TestSubscriber<Integer> ts = Flowable.range(1, 2)
          .debounce(new Function<Integer, Flowable<Integer>>() {
              @Override
              public Flowable<Integer> apply(Integer o) throws Exception {
                  if (o != 1) {
                      return Flowable.never();
                  }
                  return new Flowable<Integer>() {
                      @Override
                      protected void subscribeActual(Subscriber<? super Integer> subscriber) {
                          subscriber.onSubscribe(new BooleanSubscription());
                          ref.set(subscriber);
                      }
                  };
              }
          })
          .test();
  
          ref.get().onNext(1);
  
          ts
          .assertResult(2);
      }
  
      @Test
      public void badRequestReported() {
          TestHelper.assertBadRequestReported(Flowable.never().debounce(Functions.justFunction(Flowable.never())));
      }
  
      @Test
      public void timedDoubleOnSubscribe() {
          TestHelper.checkDoubleOnSubscribeFlowable(new Function<Flowable<Object>, Publisher<Object>>() {
              @Override
              public Publisher<Object> apply(Flowable<Object> f)
                      throws Exception {
                  return f.debounce(1, TimeUnit.SECONDS);
              }
          });
      }
  
      @Test
      public void timedDisposedIgnoredBySource() {
          final TestSubscriber<Integer> ts = new TestSubscriber<>();
  
          new Flowable<Integer>() {
              @Override
              protected void subscribeActual(
                      org.reactivestreams.Subscriber<? super Integer> s) {
                  s.onSubscribe(new BooleanSubscription());
                  ts.cancel();
                  s.onNext(1);
                  s.onComplete();
              }
          }
          .debounce(1, TimeUnit.SECONDS)
          .subscribe(ts);
      }
  
      @Test
      public void timedBadRequest() {
          TestHelper.assertBadRequestReported(Flowable.never().debounce(1, TimeUnit.SECONDS));
      }
  
      @Test
      public void timedLateEmit() {
          TestSubscriber<Integer> ts = new TestSubscriber<>();
          DebounceTimedSubscriber<Integer> sub = new DebounceTimedSubscriber<>(
                  ts, 1, TimeUnit.SECONDS, new TestScheduler().createWorker(), null);
  
          sub.onSubscribe(new BooleanSubscription());
  
          DebounceEmitter<Integer> de = new DebounceEmitter<>(1, 50, sub);
          de.emit();
          de.emit();
  
          ts.assertEmpty();
      }
  
      @Test
      public void timedError() {
          Flowable.error(new TestException())
          .debounce(1, TimeUnit.SECONDS)
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void debounceOnEmpty() {
          Flowable.empty().debounce(new Function<Object, Publisher<Object>>() {
              @Override
              public Publisher<Object> apply(Object o) {
                  return Flowable.just(new Object());
              }
          }).subscribe();
      }
  }
  