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.single;
  
  import static org.junit.Assert.*;
  
  import java.util.*;
  import java.util.concurrent.TimeUnit;
  
  import org.junit.Test;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.core.Observer;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.exceptions.TestException;
  import io.reactivex.rxjava3.functions.Function;
  import io.reactivex.rxjava3.internal.util.CrashingIterable;
  import io.reactivex.rxjava3.operators.QueueDisposable;
  import io.reactivex.rxjava3.operators.QueueFuseable;
  import io.reactivex.rxjava3.schedulers.Schedulers;
  import io.reactivex.rxjava3.testsupport.*;
  
  public class SingleFlatMapIterableObservableTest extends RxJavaTest {
  
      @Test
      public void normal() {
  
          Single.just(1).flattenAsObservable(new Function<Integer, Iterable<Integer>>() {
              @Override
              public Iterable<Integer> apply(Integer v) throws Exception {
                  return Arrays.asList(v, v + 1);
              }
          })
          .test()
          .assertResult(1, 2);
      }
  
      @Test
      public void emptyIterable() {
  
          Single.just(1).flattenAsObservable(new Function<Integer, Iterable<Integer>>() {
              @Override
              public Iterable<Integer> apply(Integer v) throws Exception {
                  return Collections.<Integer>emptyList();
              }
          })
          .test()
          .assertResult();
      }
  
      @Test
      public void error() {
  
          Single.<Integer>error(new TestException()).flattenAsObservable(new Function<Integer, Iterable<Integer>>() {
              @Override
              public Iterable<Integer> apply(Integer v) throws Exception {
                  return Arrays.asList(v, v + 1);
              }
          })
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void take() {
          Single.just(1).flattenAsObservable(new Function<Integer, Iterable<Integer>>() {
              @Override
              public Iterable<Integer> apply(Integer v) throws Exception {
                  return Arrays.asList(v, v + 1);
              }
          })
          .take(1)
          .test()
          .assertResult(1);
      }
  
      @Test
      public void fused() {
          TestObserverEx<Integer> to = new TestObserverEx<>(QueueFuseable.ANY);
  
          Single.just(1).flattenAsObservable(new Function<Integer, Iterable<Integer>>() {
              @Override
              public Iterable<Integer> apply(Integer v) throws Exception {
                  return Arrays.asList(v, v + 1);
              }
          })
          .subscribe(to);
  
          to.assertFuseable()
          .assertFusionMode(QueueFuseable.ASYNC)
          .assertResult(1, 2);
          ;
      }
  
      @Test
      public void fusedNoSync() {
          TestObserverEx<Integer> to = new TestObserverEx<>(QueueFuseable.SYNC);
  
          Single.just(1).flattenAsObservable(new Function<Integer, Iterable<Integer>>() {
              @Override
              public Iterable<Integer> apply(Integer v) throws Exception {
                  return Arrays.asList(v, v + 1);
              }
          })
          .subscribe(to);
  
          to.assertFuseable()
          .assertFusionMode(QueueFuseable.NONE)
          .assertResult(1, 2);
          ;
      }
  
      @Test
      public void iteratorCrash() {
  
          Single.just(1).flattenAsObservable(new Function<Integer, Iterable<Integer>>() {
              @Override
              public Iterable<Integer> apply(Integer v) throws Exception {
                  return new CrashingIterable(1, 100, 100);
              }
          })
          .to(TestHelper.<Integer>testConsumer())
          .assertFailureAndMessage(TestException.class, "iterator()");
      }
  
      @Test
      public void hasNextCrash() {
  
          Single.just(1).flattenAsObservable(new Function<Integer, Iterable<Integer>>() {
              @Override
              public Iterable<Integer> apply(Integer v) throws Exception {
                  return new CrashingIterable(100, 1, 100);
              }
          })
          .to(TestHelper.<Integer>testConsumer())
          .assertFailureAndMessage(TestException.class, "hasNext()");
      }
  
      @Test
      public void nextCrash() {
  
          Single.just(1).flattenAsObservable(new Function<Integer, Iterable<Integer>>() {
              @Override
              public Iterable<Integer> apply(Integer v) throws Exception {
                  return new CrashingIterable(100, 100, 1);
              }
          })
          .to(TestHelper.<Integer>testConsumer())
          .assertFailureAndMessage(TestException.class, "next()");
      }
  
      @Test
      public void hasNextCrash2() {
  
          Single.just(1).flattenAsObservable(new Function<Integer, Iterable<Integer>>() {
              @Override
              public Iterable<Integer> apply(Integer v) throws Exception {
                  return new CrashingIterable(100, 2, 100);
              }
          })
          .to(TestHelper.<Integer>testConsumer())
          .assertFailureAndMessage(TestException.class, "hasNext()", 0);
      }
  
      @Test
      public void doubleOnSubscribe() {
          TestHelper.checkDoubleOnSubscribeSingleToObservable(new Function<Single<Object>, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Single<Object> o) throws Exception {
                  return o.flattenAsObservable(new Function<Object, Iterable<Integer>>() {
                      @Override
                      public Iterable<Integer> apply(Object v) throws Exception {
                          return Collections.singleton(1);
                      }
                  });
              }
          });
      }
  
      @Test
      public void dispose() {
          TestHelper.checkDisposed(Single.just(1).flattenAsObservable(new Function<Object, Iterable<Integer>>() {
                      @Override
                      public Iterable<Integer> apply(Object v) throws Exception {
                          return Collections.singleton(1);
                      }
                  }));
      }
  
      @Test
      public void async1() {
          Single.just(1)
          .flattenAsObservable(new Function<Object, Iterable<Integer>>() {
                      @Override
                      public Iterable<Integer> apply(Object v) throws Exception {
                          Integer[] array = new Integer[1000 * 1000];
                          Arrays.fill(array, 1);
                          return Arrays.asList(array);
                      }
                  })
          .hide()
          .observeOn(Schedulers.single())
          .to(TestHelper.<Integer>testConsumer())
          .awaitDone(5, TimeUnit.SECONDS)
          .assertSubscribed()
          .assertValueCount(1000 * 1000)
          .assertNoErrors()
          .assertComplete();
      }
  
      @Test
      public void async2() {
          Single.just(1)
          .flattenAsObservable(new Function<Object, Iterable<Integer>>() {
                      @Override
                      public Iterable<Integer> apply(Object v) throws Exception {
                          Integer[] array = new Integer[1000 * 1000];
                          Arrays.fill(array, 1);
                          return Arrays.asList(array);
                      }
                  })
          .observeOn(Schedulers.single())
          .to(TestHelper.<Integer>testConsumer())
          .awaitDone(5, TimeUnit.SECONDS)
          .assertSubscribed()
          .assertValueCount(1000 * 1000)
          .assertNoErrors()
          .assertComplete();
      }
  
      @Test
      public void async3() {
          Single.just(1)
          .flattenAsObservable(new Function<Object, Iterable<Integer>>() {
                      @Override
                      public Iterable<Integer> apply(Object v) throws Exception {
                          Integer[] array = new Integer[1000 * 1000];
                          Arrays.fill(array, 1);
                          return Arrays.asList(array);
                      }
                  })
          .take(500 * 1000)
          .observeOn(Schedulers.single())
          .to(TestHelper.<Integer>testConsumer())
          .awaitDone(5, TimeUnit.SECONDS)
          .assertSubscribed()
          .assertValueCount(500 * 1000)
          .assertNoErrors()
          .assertComplete();
      }
  
      @Test
      public void async4() {
          Single.just(1)
          .flattenAsObservable(new Function<Object, Iterable<Integer>>() {
                      @Override
                      public Iterable<Integer> apply(Object v) throws Exception {
                          Integer[] array = new Integer[1000 * 1000];
                          Arrays.fill(array, 1);
                          return Arrays.asList(array);
                      }
                  })
          .observeOn(Schedulers.single())
          .take(500 * 1000)
          .to(TestHelper.<Integer>testConsumer())
          .awaitDone(5, TimeUnit.SECONDS)
          .assertSubscribed()
          .assertValueCount(500 * 1000)
          .assertNoErrors()
          .assertComplete();
      }
  
      @Test
      public void fusedEmptyCheck() {
          Single.just(1)
          .flattenAsObservable(new Function<Object, Iterable<Integer>>() {
                      @Override
                      public Iterable<Integer> apply(Object v) throws Exception {
                          return Arrays.asList(1, 2, 3);
                      }
          }).subscribe(new Observer<Integer>() {
              QueueDisposable<Integer> qd;
              @SuppressWarnings("unchecked")
              @Override
              public void onSubscribe(Disposable d) {
                  qd = (QueueDisposable<Integer>)d;
  
                  assertEquals(QueueFuseable.ASYNC, qd.requestFusion(QueueFuseable.ANY));
              }
  
              @Override
              public void onNext(Integer value) {
                  assertFalse(qd.isEmpty());
  
                  qd.clear();
  
                  assertTrue(qd.isEmpty());
  
                  qd.dispose();
              }
  
              @Override
              public void onError(Throwable e) {
              }
  
              @Override
              public void onComplete() {
              }
          });
      }
  }
  