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.List;
  import java.util.concurrent.Callable;
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.junit.Test;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.exceptions.*;
  import io.reactivex.rxjava3.functions.*;
  import io.reactivex.rxjava3.internal.functions.Functions;
  import io.reactivex.rxjava3.internal.operators.observable.ObservableConcatMapSchedulerTest.EmptyDisposingObservable;
  import io.reactivex.rxjava3.observers.TestObserver;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  import io.reactivex.rxjava3.subjects.*;
  import io.reactivex.rxjava3.testsupport.TestHelper;
  
  public class ObservableConcatMapTest extends RxJavaTest {
  
      @Test
      public void asyncFused() {
          UnicastSubject<Integer> us = UnicastSubject.create();
  
          TestObserver<Integer> to = us.concatMap(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  return Observable.range(v, 2);
              }
          })
          .test();
  
          us.onNext(1);
          us.onComplete();
  
          to.assertResult(1, 2);
      }
  
      @Test
      public void dispose() {
          TestHelper.checkDisposed(Observable.<Integer>just(1).hide()
          .concatMap(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  return Observable.error(new TestException());
              }
          }));
      }
  
      @Test
      public void dispose2() {
          TestHelper.checkDisposed(Observable.<Integer>just(1).hide()
          .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  return Observable.error(new TestException());
              }
          }));
      }
  
      @Test
      public void mainError() {
          Observable.<Integer>error(new TestException())
          .concatMap(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  return Observable.range(v, 2);
              }
          })
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void innerError() {
          Observable.<Integer>just(1).hide()
          .concatMap(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  return Observable.error(new TestException());
              }
          })
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void mainErrorDelayed() {
          Observable.<Integer>error(new TestException())
          .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  return Observable.range(v, 2);
              }
          })
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void innerErrorDelayError() {
          Observable.<Integer>just(1).hide()
          .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  return Observable.error(new TestException());
              }
          })
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void innerErrorDelayError2() {
          Observable.<Integer>just(1).hide()
          .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  return Observable.fromCallable(new Callable<Integer>() {
                      @Override
                      public Integer call() throws Exception {
                          throw new TestException();
                      }
                  });
              }
          })
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void badSource() {
          List<Throwable> errors = TestHelper.trackPluginErrors();
          try {
              new Observable<Integer>() {
                  @Override
                  protected void subscribeActual(Observer<? super Integer> observer) {
                      observer.onSubscribe(Disposable.empty());
  
                      observer.onNext(1);
                      observer.onComplete();
                      observer.onNext(2);
                      observer.onError(new TestException());
                      observer.onComplete();
                  }
              }
              .concatMap(new Function<Integer, ObservableSource<Integer>>() {
                  @Override
                  public ObservableSource<Integer> apply(Integer v) throws Exception {
                      return Observable.range(v, 2);
                  }
              })
              .test()
              .assertResult(1, 2);
  
              TestHelper.assertUndeliverable(errors, 0, TestException.class);
          } finally {
              RxJavaPlugins.reset();
          }
      }
  
      @Test
      public void badSourceDelayError() {
          List<Throwable> errors = TestHelper.trackPluginErrors();
          try {
              new Observable<Integer>() {
                  @Override
                  protected void subscribeActual(Observer<? super Integer> observer) {
                      observer.onSubscribe(Disposable.empty());
  
                      observer.onNext(1);
                      observer.onComplete();
                      observer.onNext(2);
                      observer.onError(new TestException());
                      observer.onComplete();
                  }
              }
              .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
                  @Override
                  public ObservableSource<Integer> apply(Integer v) throws Exception {
                      return Observable.range(v, 2);
                  }
              })
              .test()
              .assertResult(1, 2);
  
              TestHelper.assertUndeliverable(errors, 0, TestException.class);
          } finally {
              RxJavaPlugins.reset();
          }
      }
  
      @Test
      public void normalDelayErrors() {
          Observable.just(1).hide()
          .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  return Observable.range(v, 2);
              }
          })
          .test()
          .assertResult(1, 2);
      }
  
      @Test
      public void normalDelayErrorsTillTheEnd() {
          Observable.just(1).hide()
          .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  return Observable.range(v, 2);
              }
          }, true, 16)
          .test()
          .assertResult(1, 2);
      }
  
      @Test
      public void onErrorRace() {
          for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
              List<Throwable> errors = TestHelper.trackPluginErrors();
              try {
                  final PublishSubject<Integer> ps1 = PublishSubject.create();
                  final PublishSubject<Integer> ps2 = PublishSubject.create();
  
                  TestObserver<Integer> to = ps1.concatMap(new Function<Integer, ObservableSource<Integer>>() {
                      @Override
                      public ObservableSource<Integer> apply(Integer v) throws Exception {
                          return ps2;
                      }
                  }).test();
  
                  final TestException ex1 = new TestException();
                  final TestException ex2 = new TestException();
  
                  Runnable r1 = new Runnable() {
                      @Override
                      public void run() {
                          ps1.onError(ex1);
                      }
                  };
                  Runnable r2 = new Runnable() {
                      @Override
                      public void run() {
                          ps2.onError(ex2);
                      }
                  };
  
                  TestHelper.race(r1, r2);
  
                  to.assertFailure(TestException.class);
  
                  if (!errors.isEmpty()) {
                      TestHelper.assertError(errors, 0, TestException.class);
                  }
              } finally {
                  RxJavaPlugins.reset();
              }
          }
      }
  
      @Test
      public void mapperThrows() {
          Observable.just(1).hide()
          .concatMap(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  throw new TestException();
              }
          })
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void fusedPollThrows() {
          Observable.just(1)
          .map(new Function<Integer, Integer>() {
              @Override
              public Integer apply(Integer v) throws Exception {
                  throw new TestException();
              }
          })
          .concatMap(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  return Observable.range(v, 2);
              }
          })
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void fusedPollThrowsDelayError() {
          Observable.just(1)
          .map(new Function<Integer, Integer>() {
              @Override
              public Integer apply(Integer v) throws Exception {
                  throw new TestException();
              }
          })
          .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  return Observable.range(v, 2);
              }
          })
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void mapperThrowsDelayError() {
          Observable.just(1).hide()
          .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  throw new TestException();
              }
          })
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void badInnerDelayError() {
          @SuppressWarnings("rawtypes")
          final Observer[] o = { null };
  
          List<Throwable> errors = TestHelper.trackPluginErrors();
  
          try {
              Observable.just(1).hide()
              .concatMapDelayError(new Function<Integer, ObservableSource<Integer>>() {
                  @Override
                  public ObservableSource<Integer> apply(Integer v) throws Exception {
                      return new Observable<Integer>() {
                          @Override
                          protected void subscribeActual(Observer<? super Integer> observer) {
                              o[0] = observer;
                              observer.onSubscribe(Disposable.empty());
                              observer.onComplete();
                          }
                      };
                  }
              })
              .test()
              .assertResult();
  
              o[0].onError(new TestException());
  
              TestHelper.assertUndeliverable(errors, 0, TestException.class);
          } finally {
              RxJavaPlugins.reset();
          }
      }
  
      @Test
      public void concatReportsDisposedOnComplete() {
          final Disposable[] disposable = { null };
  
          Observable.fromArray(Observable.just(1), Observable.just(2))
          .hide()
          .concatMap(Functions.<Observable<Integer>>identity())
          .subscribe(new Observer<Integer>() {
  
              @Override
              public void onSubscribe(Disposable d) {
                  disposable[0] = d;
              }
  
              @Override
              public void onNext(Integer t) {
              }
  
              @Override
              public void onError(Throwable e) {
              }
  
              @Override
              public void onComplete() {
              }
          });
  
          assertTrue(disposable[0].isDisposed());
      }
  
      @Test
      public void concatReportsDisposedOnError() {
          final Disposable[] disposable = { null };
  
          Observable.fromArray(Observable.just(1), Observable.<Integer>error(new TestException()))
          .hide()
          .concatMap(Functions.<Observable<Integer>>identity())
          .subscribe(new Observer<Integer>() {
  
              @Override
              public void onSubscribe(Disposable d) {
                  disposable[0] = d;
              }
  
              @Override
              public void onNext(Integer t) {
              }
  
              @Override
              public void onError(Throwable e) {
              }
  
              @Override
              public void onComplete() {
              }
          });
  
          assertTrue(disposable[0].isDisposed());
      }
  
      @Test
      public void reentrantNoOverflow() {
          List<Throwable> errors = TestHelper.trackPluginErrors();
          try {
              final PublishSubject<Integer> ps = PublishSubject.create();
  
              TestObserver<Integer> to = ps.concatMap(new Function<Integer, Observable<Integer>>() {
                  @Override
                  public Observable<Integer> apply(Integer v)
                          throws Exception {
                      return Observable.just(v + 1);
                  }
              }, 1)
              .subscribeWith(new TestObserver<Integer>() {
                  @Override
                  public void onNext(Integer t) {
                      super.onNext(t);
                      if (t == 1) {
                          for (int i = 1; i < 10; i++) {
                              ps.onNext(i);
                          }
                          ps.onComplete();
                      }
                  }
              });
  
              ps.onNext(0);
  
              if (!errors.isEmpty()) {
                  to.onError(new CompositeException(errors));
              }
  
              to.assertResult(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
          } finally {
              RxJavaPlugins.reset();
          }
      }
  
      @Test
      public void reentrantNoOverflowHidden() {
          final PublishSubject<Integer> ps = PublishSubject.create();
  
          TestObserver<Integer> to = ps.concatMap(new Function<Integer, Observable<Integer>>() {
              @Override
              public Observable<Integer> apply(Integer v)
                      throws Exception {
                  return Observable.just(v + 1).hide();
              }
          }, 1)
          .subscribeWith(new TestObserver<Integer>() {
              @Override
              public void onNext(Integer t) {
                  super.onNext(t);
                  if (t == 1) {
                      for (int i = 1; i < 10; i++) {
                          ps.onNext(i);
                      }
                      ps.onComplete();
                  }
              }
          });
  
          ps.onNext(0);
  
          to.assertResult(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
      }
  
      @Test
      public void noCancelPrevious() {
          final AtomicInteger counter = new AtomicInteger();
  
          Observable.range(1, 5)
          .concatMap(new Function<Integer, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Integer v) throws Exception {
                  return Observable.just(v).doOnDispose(new Action() {
                      @Override
                      public void run() throws Exception {
                          counter.getAndIncrement();
                      }
                  });
              }
          })
          .test()
          .assertResult(1, 2, 3, 4, 5);
  
          assertEquals(0, counter.get());
      }
  
      @Test
      public void undeliverableUponCancel() {
          TestHelper.checkUndeliverableUponCancel(new ObservableConverter<Integer, Observable<Integer>>() {
              @Override
              public Observable<Integer> apply(Observable<Integer> upstream) {
                  return upstream.concatMap(new Function<Integer, Observable<Integer>>() {
                      @Override
                      public Observable<Integer> apply(Integer v) throws Throwable {
                          return Observable.just(v).hide();
                      }
                  });
              }
          });
      }
  
      @Test
      public void undeliverableUponCancelDelayError() {
          TestHelper.checkUndeliverableUponCancel(new ObservableConverter<Integer, Observable<Integer>>() {
              @Override
              public Observable<Integer> apply(Observable<Integer> upstream) {
                  return upstream.concatMapDelayError(new Function<Integer, Observable<Integer>>() {
                      @Override
                      public Observable<Integer> apply(Integer v) throws Throwable {
                          return Observable.just(v).hide();
                      }
                  }, false, 2);
              }
          });
      }
  
      @Test
      public void undeliverableUponCancelDelayErrorTillEnd() {
          TestHelper.checkUndeliverableUponCancel(new ObservableConverter<Integer, Observable<Integer>>() {
              @Override
              public Observable<Integer> apply(Observable<Integer> upstream) {
                  return upstream.concatMapDelayError(new Function<Integer, Observable<Integer>>() {
                      @Override
                      public Observable<Integer> apply(Integer v) throws Throwable {
                          return Observable.just(v).hide();
                      }
                  }, true, 2);
              }
          });
      }
  
      @Test
      public void doubleOnSubscribe() {
          TestHelper.checkDoubleOnSubscribeObservable(o -> o.concatMap(v -> Observable.never()));
      }
  
      @Test
      public void doubleOnSubscribeDelayError() {
          TestHelper.checkDoubleOnSubscribeObservable(o -> o.concatMapDelayError(v -> Observable.never()));
      }
  
      @Test
      public void scalarXMap() {
          Observable.fromCallable(() -> 1)
          .concatMap(v -> Observable.just(2).hide())
          .test()
          .assertResult(2);
      }
  
      @Test
      public void rejectedFusion() {
          TestHelper.rejectObservableFusion()
          .concatMap(v  -> Observable.never())
          .test();
      }
  
      @Test
      public void rejectedFusionDelayError() {
          TestHelper.rejectObservableFusion()
          .concatMapDelayError(v  -> Observable.never())
          .test();
      }
  
      @Test
      public void asyncFusedDelayError() {
          UnicastSubject<Integer> uc = UnicastSubject.create();
  
          TestObserver<Integer> to = uc.concatMapDelayError(v -> Observable.just(v).hide())
          .test();
  
          uc.onNext(1);
          uc.onComplete();
  
          to.assertResult(1);
      }
  
      @Test
      public void scalarInnerJustDelayError() {
          Observable.just(1)
          .hide()
          .concatMapDelayError(v -> Observable.just(v))
          .test()
          .assertResult(1);
      }
  
      @Test
      public void scalarInnerEmptyDelayError() {
          Observable.just(1)
          .hide()
          .concatMapDelayError(v -> Observable.empty())
          .test()
          .assertResult();
      }
  
      @Test
      public void scalarInnerJustDisposeDelayError() {
          TestObserver<Integer> to = new TestObserver<>();
  
          Observable.just(1)
          .hide()
          .concatMapDelayError(v -> Observable.fromCallable(() -> {
              to.dispose();
              return 1;
          }))
          .subscribe(to);
  
          to.assertEmpty();
      }
  
      @Test
      public void scalarInnerEmptyDisposeDelayError() {
          TestObserver<Object> to = new TestObserver<>();
  
          Observable.just(1)
          .hide()
          .concatMapDelayError(v -> new EmptyDisposingObservable(to))
          .subscribe(to);
  
          to.assertEmpty();
      }
  
      @Test
      public void delayErrorInnerActive() {
          PublishSubject<Integer> ps = PublishSubject.create();
  
          TestObserver<Integer> to = Observable.range(1, 5)
          .hide()
          .concatMapDelayError(v -> ps)
          .test();
  
          ps.onComplete();
  
          to.assertResult();
      }
  }
  