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 java.util.*;
  import java.util.concurrent.TimeUnit;
  
  import org.junit.Test;
  import org.reactivestreams.*;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.exceptions.*;
  import io.reactivex.rxjava3.internal.operators.flowable.BlockingFlowableIterable.BlockingFlowableIterator;
  import io.reactivex.rxjava3.internal.subscriptions.BooleanSubscription;
  import io.reactivex.rxjava3.processors.PublishProcessor;
  import io.reactivex.rxjava3.schedulers.Schedulers;
  
  public class BlockingFlowableToIteratorTest extends RxJavaTest {
  
      @Test
      public void toIterator() {
          Flowable<String> obs = Flowable.just("one", "two", "three");
  
          Iterator<String> it = obs.blockingIterable().iterator();
  
          assertTrue(it.hasNext());
          assertEquals("one", it.next());
  
          assertTrue(it.hasNext());
          assertEquals("two", it.next());
  
          assertTrue(it.hasNext());
          assertEquals("three", it.next());
  
          assertFalse(it.hasNext());
  
      }
  
      @Test(expected = TestException.class)
      public void toIteratorWithException() {
          Flowable<String> obs = Flowable.unsafeCreate(new Publisher<String>() {
  
              @Override
              public void subscribe(Subscriber<? super String> subscriber) {
                  subscriber.onSubscribe(new BooleanSubscription());
                  subscriber.onNext("one");
                  subscriber.onError(new TestException());
              }
          });
  
          Iterator<String> it = obs.blockingIterable().iterator();
  
          assertTrue(it.hasNext());
          assertEquals("one", it.next());
  
          assertTrue(it.hasNext());
          it.next();
      }
  
      @Test
      public void iteratorExertBackpressure() {
          final Counter src = new Counter();
  
          Flowable<Integer> obs = Flowable.fromIterable(new Iterable<Integer>() {
              @Override
              public Iterator<Integer> iterator() {
                  return src;
              }
          });
  
          Iterator<Integer> it = obs.blockingIterable().iterator();
          while (it.hasNext()) {
              // Correct backpressure should cause this interleaved behavior.
              // We first request RxRingBuffer.SIZE. Then in increments of
              // SubscriberIterator.LIMIT.
              int i = it.next();
              int expected = i - (i % (Flowable.bufferSize() - (Flowable.bufferSize() >> 2))) + Flowable.bufferSize();
              expected = Math.min(expected, Counter.MAX);
  
              assertEquals(expected, src.count);
          }
      }
  
      public static final class Counter implements Iterator<Integer> {
          static final int MAX = 5 * Flowable.bufferSize();
          public int count;
  
          @Override
          public boolean hasNext() {
              return count < MAX;
          }
  
          @Override
          public Integer next() {
              return ++count;
          }
  
          @Override
          public void remove() {
              throw new UnsupportedOperationException();
          }
      }
  
      @Test(expected = UnsupportedOperationException.class)
      public void remove() {
          BlockingFlowableIterator<Integer> it = new BlockingFlowableIterator<>(128);
          it.remove();
      }
  
      @Test
      public void dispose() {
          BlockingFlowableIterator<Integer> it = new BlockingFlowableIterator<>(128);
  
          assertFalse(it.isDisposed());
  
          it.dispose();
  
          assertTrue(it.isDisposed());
      }
  
      @Test
      public void interruptWait() {
          BlockingFlowableIterator<Integer> it = new BlockingFlowableIterator<>(128);
  
          try {
              Thread.currentThread().interrupt();
  
              it.hasNext();
          } catch (RuntimeException ex) {
              assertTrue(ex.toString(), ex.getCause() instanceof InterruptedException);
          }
      }
  
      @Test(expected = NoSuchElementException.class)
      public void emptyThrowsNoSuch() {
          BlockingFlowableIterator<Integer> it = new BlockingFlowableIterator<>(128);
          it.onComplete();
          it.next();
      }
  
      @Test(expected = QueueOverflowException.class)
      public void overflowQueue() {
          Iterator<Integer> it = new Flowable<Integer>() {
              @Override
              protected void subscribeActual(Subscriber<? super Integer> s) {
                  s.onSubscribe(new BooleanSubscription());
                  s.onNext(1);
                  s.onNext(2);
              }
          }
          .blockingIterable(1)
          .iterator();
  
          it.next();
      }
  
      @Test(expected = NoSuchElementException.class)
      public void disposedIteratorHasNextReturns() {
          Iterator<Integer> it = PublishProcessor.<Integer>create()
                  .blockingIterable().iterator();
          ((Disposable)it).dispose();
          assertFalse(it.hasNext());
          it.next();
      }
  
      @Test
      public void asyncDisposeUnblocks() {
          final Iterator<Integer> it = PublishProcessor.<Integer>create()
                  .blockingIterable().iterator();
  
          Schedulers.single().scheduleDirect(new Runnable() {
              @Override
              public void run() {
                  ((Disposable)it).dispose();
              }
          }, 1, TimeUnit.SECONDS);
  
          assertFalse(it.hasNext());
      }
  }
  