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.observable;
  
  import static org.junit.Assert.*;
  
  import java.util.*;
  import java.util.concurrent.TimeUnit;
  
  import org.junit.*;
  
  import io.reactivex.rxjava3.core.Observable;
  import io.reactivex.rxjava3.core.Observer;
  import io.reactivex.rxjava3.core.RxJavaTest;
  import io.reactivex.rxjava3.exceptions.TestException;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  import io.reactivex.rxjava3.schedulers.TestScheduler;
  import io.reactivex.rxjava3.subjects.PublishSubject;
  import io.reactivex.rxjava3.testsupport.TestHelper;
  
  public class BlockingObservableLatestTest extends RxJavaTest {
      @Test
      public void simple() {
          TestScheduler scheduler = new TestScheduler();
  
          Observable<Long> source = Observable.interval(1, TimeUnit.SECONDS, scheduler).take(10);
  
          Iterable<Long> iter = source.blockingLatest();
  
          Iterator<Long> it = iter.iterator();
  
          // only 9 because take(10) will immediately call onComplete when receiving the 10th item
          // which onComplete will overwrite the previous value
          for (int i = 0; i < 9; i++) {
              scheduler.advanceTimeBy(1, TimeUnit.SECONDS);
  
              Assert.assertTrue(it.hasNext());
  
              Assert.assertEquals(Long.valueOf(i), it.next());
          }
  
          scheduler.advanceTimeBy(1, TimeUnit.SECONDS);
          Assert.assertFalse(it.hasNext());
      }
  
      @Test
      public void sameSourceMultipleIterators() {
          TestScheduler scheduler = new TestScheduler();
  
          Observable<Long> source = Observable.interval(1, TimeUnit.SECONDS, scheduler).take(10);
  
          Iterable<Long> iter = source.blockingLatest();
  
          for (int j = 0; j < 3; j++) {
              Iterator<Long> it = iter.iterator();
  
              // only 9 because take(10) will immediately call onComplete when receiving the 10th item
              // which onComplete will overwrite the previous value
              for (int i = 0; i < 9; i++) {
                  scheduler.advanceTimeBy(1, TimeUnit.SECONDS);
  
                  Assert.assertTrue(it.hasNext());
  
                  Assert.assertEquals(Long.valueOf(i), it.next());
              }
  
              scheduler.advanceTimeBy(1, TimeUnit.SECONDS);
              Assert.assertFalse(it.hasNext());
          }
      }
  
      @Test(expected = NoSuchElementException.class)
      public void empty() {
          Observable<Long> source = Observable.<Long> empty();
  
          Iterable<Long> iter = source.blockingLatest();
  
          Iterator<Long> it = iter.iterator();
  
          Assert.assertFalse(it.hasNext());
  
          it.next();
      }
  
      @Test(expected = NoSuchElementException.class)
      public void simpleJustNext() {
          TestScheduler scheduler = new TestScheduler();
  
          Observable<Long> source = Observable.interval(1, TimeUnit.SECONDS, scheduler).take(10);
  
          Iterable<Long> iter = source.blockingLatest();
  
          Iterator<Long> it = iter.iterator();
  
          // only 9 because take(10) will immediately call onComplete when receiving the 10th item
          // which onComplete will overwrite the previous value
          for (int i = 0; i < 10; i++) {
              scheduler.advanceTimeBy(1, TimeUnit.SECONDS);
  
              Assert.assertEquals(Long.valueOf(i), it.next());
          }
      }
  
      @Test(expected = RuntimeException.class)
      public void hasNextThrows() {
          TestScheduler scheduler = new TestScheduler();
  
          Observable<Long> source = Observable.<Long> error(new RuntimeException("Forced failure!")).subscribeOn(scheduler);
  
          Iterable<Long> iter = source.blockingLatest();
  
          Iterator<Long> it = iter.iterator();
  
          scheduler.advanceTimeBy(1, TimeUnit.SECONDS);
  
          it.hasNext();
      }
  
      @Test(expected = RuntimeException.class)
      public void nextThrows() {
          TestScheduler scheduler = new TestScheduler();
  
          Observable<Long> source = Observable.<Long> error(new RuntimeException("Forced failure!")).subscribeOn(scheduler);
  
          Iterable<Long> iter = source.blockingLatest();
          Iterator<Long> it = iter.iterator();
  
          scheduler.advanceTimeBy(1, TimeUnit.SECONDS);
  
          it.next();
      }
  
      @Test
      public void fasterSource() {
          PublishSubject<Integer> source = PublishSubject.create();
          Observable<Integer> blocker = source;
  
          Iterable<Integer> iter = blocker.blockingLatest();
          Iterator<Integer> it = iter.iterator();
  
          source.onNext(1);
  
          Assert.assertEquals(Integer.valueOf(1), it.next());
  
          source.onNext(2);
          source.onNext(3);
  
          Assert.assertEquals(Integer.valueOf(3), it.next());
  
          source.onNext(4);
          source.onNext(5);
          source.onNext(6);
  
          Assert.assertEquals(Integer.valueOf(6), it.next());
  
          source.onNext(7);
          source.onComplete();
  
          Assert.assertFalse(it.hasNext());
      }
  
      @Test(expected = UnsupportedOperationException.class)
      public void remove() {
          Observable.never().blockingLatest().iterator().remove();
      }
  
      @Test(expected = NoSuchElementException.class)
      public void empty2() {
          Observable.empty().blockingLatest().iterator().next();
      }
  
      @Test(expected = TestException.class)
      public void error() {
          Observable.error(new TestException()).blockingLatest().iterator().next();
      }
  
      @Test
      public void error2() {
          Iterator<Object> it = Observable.error(new TestException()).blockingLatest().iterator();
  
          for (int i = 0; i < 3; i++) {
              try {
                  it.hasNext();
                  fail("Should have thrown");
              } catch (TestException ex) {
                  // expected
              }
          }
      }
  
      @Test
      public void interrupted() {
          Iterator<Object> it = Observable.never().blockingLatest().iterator();
  
          Thread.currentThread().interrupt();
  
          try {
              it.hasNext();
          } catch (RuntimeException ex) {
              assertTrue(ex.toString(), ex.getCause() instanceof InterruptedException);
          }
          Thread.interrupted();
      }
  
      @SuppressWarnings("unchecked")
      @Test
      public void onError() {
          Iterator<Object> it = Observable.never().blockingLatest().iterator();
  
          List<Throwable> errors = TestHelper.trackPluginErrors();
          try {
              ((Observer<Object>)it).onError(new TestException());
  
              TestHelper.assertUndeliverable(errors, 0, TestException.class);
          } finally {
              RxJavaPlugins.reset();
          }
      }
  }
  