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 java.util.List;
  import java.util.concurrent.*;
  import java.util.concurrent.atomic.*;
  
  import org.junit.*;
  import org.reactivestreams.Publisher;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.functions.*;
  import io.reactivex.rxjava3.processors.PublishProcessor;
  import io.reactivex.rxjava3.schedulers.Schedulers;
  
  public class BufferUntilSubscriberTest extends RxJavaTest {
  
      @Test
      public void issue1677() throws InterruptedException {
          final AtomicLong counter = new AtomicLong();
          final Integer[] numbers = new Integer[5000];
          for (int i = 0; i < numbers.length; i++) {
              numbers[i] = i + 1;
          }
          final int NITERS = 250;
          final CountDownLatch latch = new CountDownLatch(NITERS);
          for (int iters = 0; iters < NITERS; iters++) {
              final CountDownLatch innerLatch = new CountDownLatch(1);
              final PublishProcessor<Void> s = PublishProcessor.create();
              final AtomicBoolean completed = new AtomicBoolean();
              Flowable.fromArray(numbers)
                      .takeUntil(s)
                      .window(50)
                      .flatMap(new Function<Flowable<Integer>, Publisher<Object>>() {
                          @Override
                          public Publisher<Object> apply(Flowable<Integer> integerObservable) {
                                  return integerObservable
                                          .subscribeOn(Schedulers.computation())
                                          .map(new Function<Integer, Object>() {
                                              @Override
                                              public Object apply(Integer integer) {
                                                      if (integer >= 5 && completed.compareAndSet(false, true)) {
                                                          s.onComplete();
                                                      }
                                                      // do some work
                                                      Math.pow(Math.random(), Math.random());
                                                      return integer * 2;
                                              }
                                          });
                          }
                      })
                      .toList()
                      .doOnSuccess(new Consumer<List<Object>>() {
                          @Override
                          public void accept(List<Object> integers) {
                                  counter.incrementAndGet();
                                  latch.countDown();
                                  innerLatch.countDown();
                          }
                      })
                      .subscribe();
              if (!innerLatch.await(30, TimeUnit.SECONDS)) {
                  Assert.fail("Failed inner latch wait, iteration " + iters);
              }
          }
          if (!latch.await(30, TimeUnit.SECONDS)) {
              Assert.fail("Incomplete! Went through " + latch.getCount() + " iterations");
          } else {
              Assert.assertEquals(NITERS, counter.get());
          }
      }
  }
  