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.any;
  import static org.mockito.Mockito.*;
  
  import java.util.List;
  import java.util.concurrent.*;
  import java.util.concurrent.atomic.AtomicBoolean;
  
  import org.junit.Test;
  import org.reactivestreams.*;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.exceptions.*;
  import io.reactivex.rxjava3.functions.*;
  import io.reactivex.rxjava3.internal.functions.Functions;
  import io.reactivex.rxjava3.internal.subscriptions.BooleanSubscription;
  import io.reactivex.rxjava3.observers.TestObserver;
  import io.reactivex.rxjava3.operators.QueueFuseable;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  import io.reactivex.rxjava3.processors.PublishProcessor;
  import io.reactivex.rxjava3.schedulers.Schedulers;
  import io.reactivex.rxjava3.subscribers.*;
  import io.reactivex.rxjava3.testsupport.*;
  
  public class FlowableOnBackpressureBufferTest extends RxJavaTest {
  
      @Test
      public void noBackpressureSupport() {
          TestSubscriber<Long> ts = new TestSubscriber<>(0L);
          // this will be ignored
          ts.request(100);
          // we take 500 so it unsubscribes
          infinite.take(500).subscribe(ts);
          // it completely ignores the `request(100)` and we get 500
          assertEquals(500, ts.values().size());
          ts.assertNoErrors();
      }
  
      @Test
      public void fixBackpressureWithBuffer() throws InterruptedException {
          final CountDownLatch l1 = new CountDownLatch(100);
          final CountDownLatch l2 = new CountDownLatch(150);
          TestSubscriber<Long> ts = new TestSubscriber<>(new DefaultSubscriber<Long>() {
  
              @Override
              protected void onStart() {
              }
  
              @Override
              public void onComplete() {
              }
  
              @Override
              public void onError(Throwable e) {
              }
  
              @Override
              public void onNext(Long t) {
                  l1.countDown();
                  l2.countDown();
              }
  
          }, 0L);
          // this will be ignored
          ts.request(100);
          // we take 500 so it unsubscribes
          infinite.subscribeOn(Schedulers.computation())
          .onBackpressureBuffer()
          .take(500)
          .subscribe(ts);
  
          // it completely ignores the `request(100)` and we get 500
          l1.await();
          assertEquals(100, ts.values().size());
          ts.request(50);
          l2.await();
          assertEquals(150, ts.values().size());
          ts.request(350);
          ts.awaitDone(5, TimeUnit.SECONDS);
          assertEquals(500, ts.values().size());
          ts.assertNoErrors();
          assertEquals(0, ts.values().get(0).intValue());
          assertEquals(499, ts.values().get(499).intValue());
      }
  
      @Test(expected = IllegalArgumentException.class)
      public void fixBackpressureBufferNegativeCapacity() throws InterruptedException {
          Flowable.empty().onBackpressureBuffer(-1);
      }
  
      @Test(expected = IllegalArgumentException.class)
      public void fixBackpressureBufferZeroCapacity() throws InterruptedException {
          Flowable.empty().onBackpressureBuffer(0);
      }
  
      @Test
      public void fixBackpressureBoundedBuffer() throws InterruptedException {
          final CountDownLatch l1 = new CountDownLatch(100);
          final CountDownLatch backpressureCallback = new CountDownLatch(1);
          TestSubscriber<Long> ts = new TestSubscriber<>(new DefaultSubscriber<Long>() {
  
              @Override
              protected void onStart() {
              }
  
              @Override
              public void onComplete() {
              }
  
              @Override
              public void onError(Throwable e) {
              }
  
              @Override
              public void onNext(Long t) {
                  l1.countDown();
              }
  
          }, 0L);
  
          ts.request(100);
          infinite.subscribeOn(Schedulers.computation())
               .onBackpressureBuffer(500, new Action() {
                   @Override
                   public void run() {
                       backpressureCallback.countDown();
                   }
               })
               /*.take(1000)*/
               .subscribe(ts);
          l1.await();
  
          ts.request(50);
  
          assertTrue(backpressureCallback.await(500, TimeUnit.MILLISECONDS));
          ts.awaitDone(1, TimeUnit.SECONDS);
          ts.assertError(MissingBackpressureException.class);
  
          int size = ts.values().size();
          assertTrue(size <= 150);  // will get up to 50 more
          assertEquals((long)ts.values().get(size - 1), size - 1);
      }
  
      static final Flowable<Long> infinite = Flowable.unsafeCreate(new Publisher<Long>() {
  
          @Override
          public void subscribe(Subscriber<? super Long> s) {
              BooleanSubscription bs = new BooleanSubscription();
              s.onSubscribe(bs);
              long i = 0;
              while (!bs.isCancelled()) {
                  s.onNext(i++);
              }
          }
  
      });
  
      private static final Action THROWS_NON_FATAL = new Action() {
  
          @Override
          public void run() {
              throw new RuntimeException();
          }
      };
  
      @Test
      public void nonFatalExceptionThrownByOnOverflowIsNotReportedByUpstream() {
           final AtomicBoolean errorOccurred = new AtomicBoolean(false);
           TestSubscriber<Long> ts = TestSubscriber.create(0);
           infinite
             .subscribeOn(Schedulers.computation())
             .doOnError(new Consumer<Throwable>() {
                   @Override
                   public void accept(Throwable t) {
                       errorOccurred.set(true);
                   }
               })
             .onBackpressureBuffer(1, THROWS_NON_FATAL)
             .subscribe(ts);
           ts.awaitDone(5, TimeUnit.SECONDS);
           assertFalse(errorOccurred.get());
      }
  
      @Test
      public void maxSize() {
          TestSubscriber<Integer> ts = TestSubscriber.create(0);
  
          Flowable.range(1, 10).onBackpressureBuffer(1).subscribe(ts);
  
          ts.assertNoValues();
          ts.assertError(MissingBackpressureException.class);
          ts.assertNotComplete();
      }
  
      @Test(expected = IllegalArgumentException.class)
      public void fixBackpressureBufferNegativeCapacity2() throws InterruptedException {
          Flowable.empty().onBackpressureBuffer(-1);
      }
  
      @Test(expected = IllegalArgumentException.class)
      public void fixBackpressureBufferZeroCapacity2() throws InterruptedException {
          Flowable.empty().onBackpressureBuffer(0);
      }
  
      @Test
      public void noDelayError() {
  
          Flowable.just(1).concatWith(Flowable.<Integer>error(new TestException()))
          .onBackpressureBuffer(false)
          .test(0L)
          .assertFailure(TestException.class);
      }
  
      @Test
      public void delayError() {
          TestSubscriber<Integer> ts = Flowable.just(1).concatWith(Flowable.<Integer>error(new TestException()))
          .onBackpressureBuffer(true)
          .test(0L)
          .assertEmpty();
  
          ts.request(1);
          ts.assertFailure(TestException.class, 1);
  
      }
  
      @Test
      public void delayErrorBuffer() {
          TestSubscriber<Integer> ts = Flowable.just(1).concatWith(Flowable.<Integer>error(new TestException()))
          .onBackpressureBuffer(16, true)
          .test(0L)
          .assertEmpty();
  
          ts.request(1);
          ts.assertFailure(TestException.class, 1);
      }
  
      @Test
      public void fusedNormal() {
          TestSubscriberEx<Integer> ts = new TestSubscriberEx<Integer>().setInitialFusionMode(QueueFuseable.ANY);
  
          Flowable.range(1, 10).onBackpressureBuffer().subscribe(ts);
  
          ts.assertFuseable()
            .assertFusionMode(QueueFuseable.ASYNC)
            .assertResult(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
      }
  
      @Test
      public void fusedError() {
          TestSubscriberEx<Integer> ts = new TestSubscriberEx<Integer>().setInitialFusionMode(QueueFuseable.ANY);
  
          Flowable.<Integer>error(new TestException()).onBackpressureBuffer().subscribe(ts);
  
          ts.assertFuseable()
            .assertFusionMode(QueueFuseable.ASYNC)
            .assertFailure(TestException.class);
      }
  
      @Test
      public void fusedPreconsume() throws Exception {
  
          TestSubscriber<Integer> ts = Flowable.range(1, 1000 * 1000)
          .onBackpressureBuffer()
          .observeOn(Schedulers.single())
          .test(0L);
  
          ts.assertEmpty();
  
          Thread.sleep(100);
  
          ts.request(1000 * 1000);
  
          ts
          .awaitDone(5, TimeUnit.SECONDS)
          .assertValueCount(1000 * 1000)
          .assertNoErrors()
          .assertComplete();
      }
  
      @Test
      public void emptyDelayError() {
          Flowable.empty()
          .onBackpressureBuffer(true)
          .test()
          .assertResult();
      }
  
      @Test
      public void fusionRejected() {
          TestSubscriberEx<Integer> ts = new TestSubscriberEx<Integer>().setInitialFusionMode(QueueFuseable.SYNC);
  
          Flowable.<Integer>never().onBackpressureBuffer().subscribe(ts);
  
          ts.assertFusionMode(QueueFuseable.NONE)
          .assertEmpty();
      }
  
      @Test
      public void fusedNoConcurrentCleanDueToCancel() {
          for (int j = 0; j < TestHelper.RACE_LONG_LOOPS; j++) {
              List<Throwable> errors = TestHelper.trackPluginErrors();
              try {
                  final PublishProcessor<Integer> pp = PublishProcessor.create();
  
                  TestObserver<Integer> to = pp.onBackpressureBuffer(4, false, true)
                  .observeOn(Schedulers.io())
                  .map(Functions.<Integer>identity())
                  .observeOn(Schedulers.single())
                  .firstOrError()
                  .test();
  
                  for (int i = 0; pp.hasSubscribers(); i++) {
                      pp.onNext(i);
                  }
  
                  to
                  .awaitDone(5, TimeUnit.SECONDS)
                  ;
  
                  if (!errors.isEmpty()) {
                      throw new CompositeException(errors);
                  }
  
                  to.assertResult(0);
              } finally {
                  RxJavaPlugins.reset();
              }
          }
      }
  
      @Test
      public void doubleOnSubscribe() {
          TestHelper.checkDoubleOnSubscribeFlowable(f -> f.onBackpressureBuffer());
      }
  
      @Test
      public void badRequest() {
          TestHelper.assertBadRequestReported(Flowable.never().onBackpressureBuffer());
      }
  
      @Test
      public void onDroppedNormal() throws Throwable {
          PublishProcessor<Integer> pp = PublishProcessor.create();
  
          @SuppressWarnings("unchecked")
          Consumer<Integer> onDropped = mock(Consumer.class);
  
          TestSubscriber<Integer> ts = pp.onBackpressureBuffer(1, false, false, () -> { }, onDropped)
                  .test(0L);
  
          ts.assertEmpty();
  
          pp.onNext(1);
  
          ts.assertEmpty();
          verify(onDropped, never()).accept(any());
  
          pp.onNext(2);
  
          ts.assertFailure(MissingBackpressureException.class);
  
          verify(onDropped).accept(2);
      }
  
      @Test
      public void onDroppedCrash() throws Throwable {
          PublishProcessor<Integer> pp = PublishProcessor.create();
  
          Consumer<Integer> onDropped = v -> { throw new TestException(); };
  
          TestSubscriberEx<Integer> ts = pp.onBackpressureBuffer(1, false, false, () -> { }, onDropped)
          .subscribeWith(new TestSubscriberEx<Integer>(0L));
  
          ts.assertEmpty();
  
          pp.onNext(1);
  
          ts.assertEmpty();
  
          pp.onNext(2);
  
          ts.assertFailure(MissingBackpressureException.class);
  
          assertTrue(ts.errors().get(0).getCause() instanceof TestException);
      }
  }
  