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.observers;
  
  import org.junit.Test;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.*;
  import io.reactivex.rxjava3.observers.TestObserver;
  import io.reactivex.rxjava3.operators.SpscArrayQueue;
  import io.reactivex.rxjava3.testsupport.TestHelper;
  
  public class QueueDrainObserverTest extends RxJavaTest {
  
      static final QueueDrainObserver<Integer, Integer, Integer> createUnordered(TestObserver<Integer> to, final Disposable d) {
          return new QueueDrainObserver<Integer, Integer, Integer>(to, new SpscArrayQueue<>(4)) {
              @Override
              public void onNext(Integer t) {
                  fastPathEmit(t, false, d);
              }
  
              @Override
              public void onError(Throwable t) {
              }
  
              @Override
              public void onComplete() {
              }
  
              @Override
              public void onSubscribe(Disposable d) {
              }
  
              @Override
              public void accept(Observer<? super Integer> a, Integer v) {
                  super.accept(a, v);
                  a.onNext(v);
              }
          };
      }
  
      static final QueueDrainObserver<Integer, Integer, Integer> createOrdered(TestObserver<Integer> to, final Disposable d) {
          return new QueueDrainObserver<Integer, Integer, Integer>(to, new SpscArrayQueue<>(4)) {
              @Override
              public void onNext(Integer t) {
                  fastPathOrderedEmit(t, false, d);
              }
  
              @Override
              public void onError(Throwable t) {
              }
  
              @Override
              public void onComplete() {
              }
  
              @Override
              public void onSubscribe(Disposable d) {
              }
  
              @Override
              public void accept(Observer<? super Integer> a, Integer v) {
                  super.accept(a, v);
                  a.onNext(v);
              }
          };
      }
  
      @Test
      public void unorderedSlowPath() {
          TestObserver<Integer> to = new TestObserver<>();
          Disposable d = Disposable.empty();
          QueueDrainObserver<Integer, Integer, Integer> qd = createUnordered(to, d);
          to.onSubscribe(Disposable.empty());
  
          qd.enter();
          qd.onNext(1);
  
          to.assertEmpty();
      }
  
      @Test
      public void orderedSlowPath() {
          TestObserver<Integer> to = new TestObserver<>();
          Disposable d = Disposable.empty();
          QueueDrainObserver<Integer, Integer, Integer> qd = createOrdered(to, d);
          to.onSubscribe(Disposable.empty());
  
          qd.enter();
          qd.onNext(1);
  
          to.assertEmpty();
      }
  
      @Test
      public void orderedSlowPathNonEmptyQueue() {
          TestObserver<Integer> to = new TestObserver<>();
          Disposable d = Disposable.empty();
          QueueDrainObserver<Integer, Integer, Integer> qd = createOrdered(to, d);
          to.onSubscribe(Disposable.empty());
  
          qd.queue.offer(0);
          qd.onNext(1);
  
          to.assertValuesOnly(0, 1);
      }
  
      @Test
      public void unorderedOnNextRace() {
          for (int i = 0; i < TestHelper.RACE_LONG_LOOPS; i++) {
  
              TestObserver<Integer> to = new TestObserver<>();
              Disposable d = Disposable.empty();
              final QueueDrainObserver<Integer, Integer, Integer> qd = createUnordered(to, d);
              to.onSubscribe(Disposable.empty());
  
              Runnable r1 = new Runnable() {
                  @Override
                  public void run() {
                      qd.onNext(1);
                  }
              };
  
              TestHelper.race(r1, r1);
  
              to.assertValuesOnly(1, 1);
          }
      }
  
      @Test
      public void orderedOnNextRace() {
          for (int i = 0; i < TestHelper.RACE_LONG_LOOPS; i++) {
  
              TestObserver<Integer> to = new TestObserver<>();
              Disposable d = Disposable.empty();
              final QueueDrainObserver<Integer, Integer, Integer> qd = createOrdered(to, d);
              to.onSubscribe(Disposable.empty());
  
              Runnable r1 = new Runnable() {
                  @Override
                  public void run() {
                      qd.onNext(1);
                  }
              };
  
              TestHelper.race(r1, r1);
  
              to.assertValuesOnly(1, 1);
          }
      }
  
  }
  