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.parallel;
  
  import static org.junit.Assert.*;
  
  import java.util.*;
  
  import org.junit.Test;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.exceptions.TestException;
  import io.reactivex.rxjava3.functions.*;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  import io.reactivex.rxjava3.processors.PublishProcessor;
  import io.reactivex.rxjava3.subscribers.TestSubscriber;
  import io.reactivex.rxjava3.testsupport.TestHelper;
  
  public class ParallelReduceTest extends RxJavaTest {
  
      @Test
      public void subscriberCount() {
          ParallelFlowableTest.checkSubscriberCount(Flowable.range(1, 5).parallel()
          .reduce(new Supplier<List<Integer>>() {
              @Override
              public List<Integer> get() throws Exception {
                  return new ArrayList<>();
              }
          }, new BiFunction<List<Integer>, Integer, List<Integer>>() {
              @Override
              public List<Integer> apply(List<Integer> a, Integer b) throws Exception {
                  a.add(b);
                  return a;
              }
          }));
      }
  
      @Test
      public void initialCrash() {
          Flowable.range(1, 5)
          .parallel()
          .reduce(new Supplier<List<Integer>>() {
              @Override
              public List<Integer> get() throws Exception {
                  throw new TestException();
              }
          }, new BiFunction<List<Integer>, Integer, List<Integer>>() {
              @Override
              public List<Integer> apply(List<Integer> a, Integer b) throws Exception {
                  a.add(b);
                  return a;
              }
          })
          .sequential()
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void reducerCrash() {
          Flowable.range(1, 5)
          .parallel()
          .reduce(new Supplier<List<Integer>>() {
              @Override
              public List<Integer> get() throws Exception {
                  return new ArrayList<>();
              }
          }, new BiFunction<List<Integer>, Integer, List<Integer>>() {
              @Override
              public List<Integer> apply(List<Integer> a, Integer b) throws Exception {
                  if (b == 3) {
                      throw new TestException();
                  }
                  a.add(b);
                  return a;
              }
          })
          .sequential()
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void cancel() {
          PublishProcessor<Integer> pp = PublishProcessor.create();
  
          TestSubscriber<List<Integer>> ts = pp
          .parallel()
          .reduce(new Supplier<List<Integer>>() {
              @Override
              public List<Integer> get() throws Exception {
                  return new ArrayList<>();
              }
          }, new BiFunction<List<Integer>, Integer, List<Integer>>() {
              @Override
              public List<Integer> apply(List<Integer> a, Integer b) throws Exception {
                  a.add(b);
                  return a;
              }
          })
          .sequential()
          .test();
  
          assertTrue(pp.hasSubscribers());
  
          ts.cancel();
  
          assertFalse(pp.hasSubscribers());
      }
  
      @Test
      public void error() {
          Flowable.<Integer>error(new TestException())
          .parallel()
          .reduce(new Supplier<List<Integer>>() {
              @Override
              public List<Integer> get() throws Exception {
                  return new ArrayList<>();
              }
          }, new BiFunction<List<Integer>, Integer, List<Integer>>() {
              @Override
              public List<Integer> apply(List<Integer> a, Integer b) throws Exception {
                  a.add(b);
                  return a;
              }
          })
          .sequential()
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void doubleError() {
          List<Throwable> errors = TestHelper.trackPluginErrors();
          try {
              new ParallelInvalid()
              .reduce(new Supplier<List<Object>>() {
                  @Override
                  public List<Object> get() throws Exception {
                      return new ArrayList<>();
                  }
              }, new BiFunction<List<Object>, Object, List<Object>>() {
                  @Override
                  public List<Object> apply(List<Object> a, Object b) throws Exception {
                      a.add(b);
                      return a;
                  }
              })
              .sequential()
              .test()
              .assertFailure(TestException.class);
  
              assertFalse(errors.isEmpty());
              for (Throwable ex : errors) {
                  assertTrue(ex.toString(), ex.getCause() instanceof TestException);
              }
          } finally {
              RxJavaPlugins.reset();
          }
      }
  
      @Test
      public void doubleOnSubscribe() {
          TestHelper.checkDoubleOnSubscribeParallel(
                  pf -> pf.reduce(ArrayList::new, (a, b) -> a)
          );
      }
  }
  