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.List;
  import java.util.concurrent.*;
  
  import org.junit.Test;
  import org.reactivestreams.Subscriber;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.exceptions.*;
  import io.reactivex.rxjava3.functions.Function;
  import io.reactivex.rxjava3.internal.functions.Functions;
  import io.reactivex.rxjava3.internal.subscriptions.BooleanSubscription;
  import io.reactivex.rxjava3.plugins.RxJavaPlugins;
  import io.reactivex.rxjava3.processors.PublishProcessor;
  import io.reactivex.rxjava3.schedulers.Schedulers;
  import io.reactivex.rxjava3.subjects.MaybeSubject;
  import io.reactivex.rxjava3.subscribers.TestSubscriber;
  import io.reactivex.rxjava3.testsupport.*;
  
  public class FlowableFlatMapMaybeTest extends RxJavaTest {
  
      @Test
      public void normal() {
          Flowable.range(1, 10)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.just(v);
              }
          })
          .test()
          .assertResult(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
      }
  
      @Test
      public void normalEmpty() {
          Flowable.range(1, 10)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.empty();
              }
          })
          .test()
          .assertResult();
      }
  
      @Test
      public void normalDelayError() {
          Flowable.range(1, 10)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.just(v);
              }
          }, true, Integer.MAX_VALUE)
          .test()
          .assertResult(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
      }
  
      @Test
      public void normalAsync() {
          TestSubscriberEx<Integer> ts = Flowable.range(1, 10)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.just(v).subscribeOn(Schedulers.computation());
              }
          })
          .to(TestHelper.<Integer>testConsumer())
          .awaitDone(5, TimeUnit.SECONDS)
          .assertSubscribed()
          .assertValueCount(10)
          .assertNoErrors()
          .assertComplete();
  
          TestHelper.assertValueSet(ts, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
      }
  
      @Test
      public void normalAsyncMaxConcurrency() {
          TestSubscriberEx<Integer> ts = Flowable.range(1, 10)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.just(v).subscribeOn(Schedulers.computation());
              }
          }, false, 3)
          .to(TestHelper.<Integer>testConsumer())
          .awaitDone(5, TimeUnit.SECONDS)
          .assertSubscribed()
          .assertValueCount(10)
          .assertNoErrors()
          .assertComplete();
  
          TestHelper.assertValueSet(ts, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
       }
  
      @Test
      public void normalAsyncMaxConcurrency1() {
          Flowable.range(1, 10)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.just(v).subscribeOn(Schedulers.computation());
              }
          }, false, 1)
          .test()
          .awaitDone(5, TimeUnit.SECONDS)
          .assertResult(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
      }
  
      @Test
      public void mapperThrowsFlowable() {
          PublishProcessor<Integer> pp = PublishProcessor.create();
  
          TestSubscriber<Integer> ts = pp
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  throw new TestException();
              }
          })
          .test();
  
          assertTrue(pp.hasSubscribers());
  
          pp.onNext(1);
  
          ts.assertFailure(TestException.class);
  
          assertFalse(pp.hasSubscribers());
      }
  
      @Test
      public void mapperReturnsNullFlowable() {
          PublishProcessor<Integer> pp = PublishProcessor.create();
  
          TestSubscriber<Integer> ts = pp
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return null;
              }
          })
          .test();
  
          assertTrue(pp.hasSubscribers());
  
          pp.onNext(1);
  
          ts.assertFailure(NullPointerException.class);
  
          assertFalse(pp.hasSubscribers());
      }
  
      @Test
      public void normalDelayErrorAll() {
          TestSubscriberEx<Integer> ts = Flowable.range(1, 10).concatWith(Flowable.<Integer>error(new TestException()))
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.error(new TestException());
              }
          }, true, Integer.MAX_VALUE)
          .to(TestHelper.<Integer>testConsumer())
          .assertFailure(CompositeException.class);
  
          List<Throwable> errors = TestHelper.compositeList(ts.errors().get(0));
  
          for (int i = 0; i < 11; i++) {
              TestHelper.assertError(errors, i, TestException.class);
          }
      }
  
      @Test
      public void normalBackpressured() {
          Flowable.range(1, 10)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.just(v);
              }
          })
          .rebatchRequests(1)
          .test()
          .assertResult(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
      }
  
      @Test
      public void normalMaxConcurrent1Backpressured() {
          Flowable.range(1, 10)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.just(v);
              }
          }, false, 1)
          .rebatchRequests(1)
          .test()
          .assertResult(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
      }
  
      @Test
      public void normalMaxConcurrent2Backpressured() {
          Flowable.range(1, 10)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.just(v);
              }
          }, false, 2)
          .rebatchRequests(1)
          .test()
          .assertResult(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
      }
  
      @Test
      public void takeAsync() {
          TestSubscriberEx<Integer> ts = Flowable.range(1, 10)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.just(v).subscribeOn(Schedulers.computation());
              }
          })
          .take(2)
          .to(TestHelper.<Integer>testConsumer())
          .awaitDone(5, TimeUnit.SECONDS)
          .assertSubscribed()
          .assertValueCount(2)
          .assertNoErrors()
          .assertComplete();
  
          TestHelper.assertValueSet(ts, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
      }
  
      @Test
      public void take() {
          Flowable.range(1, 10)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.just(v);
              }
          })
          .take(2)
          .test()
          .assertResult(1, 2);
      }
  
      @Test
      public void middleError() {
          Flowable.fromArray(new String[]{"1", "a", "2"})
          .flatMapMaybe(new Function<String, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(final String s) throws NumberFormatException {
                  //return Maybe.just(Integer.valueOf(s)); //This works
                  return Maybe.fromCallable(new Callable<Integer>() {
                      @Override
                      public Integer call() throws NumberFormatException {
                          return Integer.valueOf(s);
                      }
                  });
              }
          })
          .test()
          .assertFailure(NumberFormatException.class, 1);
      }
  
      @Test
      public void disposed() {
          TestHelper.checkDisposed(PublishProcessor.<Integer>create().flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.<Integer>empty();
              }
          }));
      }
  
      @Test
      public void asyncFlatten() {
          Flowable.range(1, 1000)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.just(1).subscribeOn(Schedulers.computation());
              }
          })
          .take(500)
          .to(TestHelper.<Integer>testConsumer())
          .awaitDone(5, TimeUnit.SECONDS)
          .assertSubscribed()
          .assertValueCount(500)
          .assertNoErrors()
          .assertComplete();
      }
  
      @Test
      public void asyncFlattenNone() {
          Flowable.range(1, 1000)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.<Integer>empty().subscribeOn(Schedulers.computation());
              }
          })
          .take(500)
          .test()
          .awaitDone(5, TimeUnit.SECONDS)
          .assertResult();
      }
  
      @Test
      public void asyncFlattenNoneMaxConcurrency() {
          Flowable.range(1, 1000)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.<Integer>empty().subscribeOn(Schedulers.computation());
              }
          }, false, 128)
          .take(500)
          .test()
          .awaitDone(5, TimeUnit.SECONDS)
          .assertResult();
      }
  
      @Test
      public void asyncFlattenErrorMaxConcurrency() {
          Flowable.range(1, 1000)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  return Maybe.<Integer>error(new TestException()).subscribeOn(Schedulers.computation());
              }
          }, true, 128)
          .take(500)
          .test()
          .awaitDone(5, TimeUnit.SECONDS)
          .assertFailure(CompositeException.class);
      }
  
      @Test
      public void successError() {
          final PublishProcessor<Integer> pp = PublishProcessor.create();
  
          TestSubscriber<Integer> ts = Flowable.range(1, 2)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  if (v == 2) {
                      return pp.singleElement();
                  }
                  return Maybe.error(new TestException());
              }
          }, true, Integer.MAX_VALUE)
          .test();
  
          pp.onNext(1);
          pp.onComplete();
  
          ts
          .assertFailure(TestException.class, 1);
      }
  
      @Test
      public void completeError() {
          final PublishProcessor<Integer> pp = PublishProcessor.create();
  
          TestSubscriber<Integer> ts = Flowable.range(1, 2)
          .flatMapMaybe(new Function<Integer, MaybeSource<Integer>>() {
              @Override
              public MaybeSource<Integer> apply(Integer v) throws Exception {
                  if (v == 2) {
                      return pp.singleElement();
                  }
                  return Maybe.error(new TestException());
              }
          }, true, Integer.MAX_VALUE)
          .test();
  
          pp.onComplete();
  
          ts
          .assertFailure(TestException.class);
      }
  
      @Test
      public void doubleOnSubscribe() {
          TestHelper.checkDoubleOnSubscribeFlowable(new Function<Flowable<Object>, Flowable<Integer>>() {
              @Override
              public Flowable<Integer> apply(Flowable<Object> f) throws Exception {
                  return f.flatMapMaybe(Functions.justFunction(Maybe.just(2)));
              }
          });
      }
  
      @Test
      public void badSource() {
          List<Throwable> errors = TestHelper.trackPluginErrors();
          try {
              new Flowable<Integer>() {
                  @Override
                  protected void subscribeActual(Subscriber<? super Integer> subscriber) {
                      subscriber.onSubscribe(new BooleanSubscription());
                      subscriber.onError(new TestException("First"));
                      subscriber.onError(new TestException("Second"));
                  }
              }
              .flatMapMaybe(Functions.justFunction(Maybe.just(2)))
              .to(TestHelper.<Integer>testConsumer())
              .assertFailureAndMessage(TestException.class, "First");
  
              TestHelper.assertUndeliverable(errors, 0, TestException.class, "Second");
          } finally {
              RxJavaPlugins.reset();
          }
      }
  
      @Test
      public void badInnerSource() {
          List<Throwable> errors = TestHelper.trackPluginErrors();
          try {
              Flowable.just(1)
              .flatMapMaybe(Functions.justFunction(new Maybe<Integer>() {
                  @Override
                  protected void subscribeActual(MaybeObserver<? super Integer> observer) {
                      observer.onSubscribe(Disposable.empty());
                      observer.onError(new TestException("First"));
                      observer.onError(new TestException("Second"));
                  }
              }))
              .to(TestHelper.<Integer>testConsumer())
              .assertFailureAndMessage(TestException.class, "First");
  
              TestHelper.assertUndeliverable(errors, 0, TestException.class, "Second");
          } finally {
              RxJavaPlugins.reset();
          }
      }
  
      @Test
      public void emissionQueueTrigger() {
          final PublishProcessor<Integer> pp1 = PublishProcessor.create();
          final PublishProcessor<Integer> pp2 = PublishProcessor.create();
  
          TestSubscriber<Integer> ts = new TestSubscriber<Integer>() {
              @Override
              public void onNext(Integer t) {
                  super.onNext(t);
                  if (t == 1) {
                      pp2.onNext(2);
                      pp2.onComplete();
                  }
              }
          };
  
          Flowable.just(pp1, pp2)
                  .flatMapMaybe(new Function<PublishProcessor<Integer>, MaybeSource<Integer>>() {
                      @Override
                      public MaybeSource<Integer> apply(PublishProcessor<Integer> v) throws Exception {
                          return v.singleElement();
                      }
                  })
          .subscribe(ts);
  
          pp1.onNext(1);
          pp1.onComplete();
  
          ts.assertResult(1, 2);
      }
  
      @Test
      public void emissionQueueTrigger2() {
          final PublishProcessor<Integer> pp1 = PublishProcessor.create();
          final PublishProcessor<Integer> pp2 = PublishProcessor.create();
          final PublishProcessor<Integer> pp3 = PublishProcessor.create();
  
          TestSubscriber<Integer> ts = new TestSubscriber<Integer>() {
              @Override
              public void onNext(Integer t) {
                  super.onNext(t);
                  if (t == 1) {
                      pp2.onNext(2);
                      pp2.onComplete();
                  }
              }
          };
  
          Flowable.just(pp1, pp2, pp3)
                  .flatMapMaybe(new Function<PublishProcessor<Integer>, MaybeSource<Integer>>() {
                      @Override
                      public MaybeSource<Integer> apply(PublishProcessor<Integer> v) throws Exception {
                          return v.singleElement();
                      }
                  })
          .subscribe(ts);
  
          pp1.onNext(1);
          pp1.onComplete();
  
          pp3.onComplete();
  
          ts.assertResult(1, 2);
      }
  
      @Test
      public void disposeInner() {
          final TestSubscriber<Object> ts = new TestSubscriber<>();
  
          Flowable.just(1).flatMapMaybe(new Function<Integer, MaybeSource<Object>>() {
              @Override
              public MaybeSource<Object> apply(Integer v) throws Exception {
                  return new Maybe<Object>() {
                      @Override
                      protected void subscribeActual(MaybeObserver<? super Object> observer) {
                          observer.onSubscribe(Disposable.empty());
  
                          assertFalse(((Disposable)observer).isDisposed());
  
                          ts.cancel();
  
                          assertTrue(((Disposable)observer).isDisposed());
                      }
                  };
              }
          })
          .subscribe(ts);
  
          ts
          .assertEmpty();
      }
  
      @Test
      public void innerSuccessCompletesAfterMain() {
          PublishProcessor<Integer> pp = PublishProcessor.create();
  
          TestSubscriber<Integer> ts = Flowable.just(1).flatMapMaybe(Functions.justFunction(pp.singleElement()))
          .test();
  
          pp.onNext(2);
          pp.onComplete();
  
          ts
          .assertResult(2);
      }
  
      @Test
      public void backpressure() {
          TestSubscriber<Integer> ts = Flowable.just(1)
          .flatMapMaybe(Functions.justFunction(Maybe.just(2)))
          .test(0L)
          .assertEmpty();
  
          ts.request(1);
          ts.assertResult(2);
      }
  
      @Test
      public void error() {
          Flowable.just(1)
          .flatMapMaybe(Functions.justFunction(Maybe.<Integer>error(new TestException())))
          .test(0L)
          .assertFailure(TestException.class);
      }
  
      @Test
      public void errorDelayed() {
          Flowable.just(1)
          .flatMapMaybe(Functions.justFunction(Maybe.<Integer>error(new TestException())), true, 16)
          .test(0L)
          .assertFailure(TestException.class);
      }
  
      @Test
      public void requestCancelRace() {
          for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
              final TestSubscriber<Integer> ts = Flowable.just(1).concatWith(Flowable.<Integer>never())
              .flatMapMaybe(Functions.justFunction(Maybe.just(2))).test(0);
  
              Runnable r1 = new Runnable() {
                  @Override
                  public void run() {
                      ts.request(1);
                  }
              };
              Runnable r2 = new Runnable() {
                  @Override
                  public void run() {
                      ts.cancel();
                  }
              };
  
              TestHelper.race(r1, r2);
          }
      }
  
      @Test
      public void undeliverableUponCancel() {
          TestHelper.checkUndeliverableUponCancel(new FlowableConverter<Integer, Flowable<Integer>>() {
              @Override
              public Flowable<Integer> apply(Flowable<Integer> upstream) {
                  return upstream.flatMapMaybe(new Function<Integer, Maybe<Integer>>() {
                      @Override
                      public Maybe<Integer> apply(Integer v) throws Throwable {
                          return Maybe.just(v).hide();
                      }
                  });
              }
          });
      }
  
      @Test
      public void undeliverableUponCancelDelayError() {
          TestHelper.checkUndeliverableUponCancel(new FlowableConverter<Integer, Flowable<Integer>>() {
              @Override
              public Flowable<Integer> apply(Flowable<Integer> upstream) {
                  return upstream.flatMapMaybe(new Function<Integer, Maybe<Integer>>() {
                      @Override
                      public Maybe<Integer> apply(Integer v) throws Throwable {
                          return Maybe.just(v).hide();
                      }
                  }, true, 2);
              }
          });
      }
  
      @Test
      public void badRequest() {
          TestHelper.assertBadRequestReported(Flowable.never().flatMapMaybe(v -> Maybe.never()));
      }
  
      @Test
      public void successRace() {
          for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
              MaybeSubject<Integer> ss1 = MaybeSubject.create();
              MaybeSubject<Integer> ss2 = MaybeSubject.create();
  
              TestSubscriber<Integer> ts = Flowable.just(ss1, ss2).flatMapMaybe(v -> v)
              .test();
  
              TestHelper.race(
                      () -> ss1.onSuccess(1),
                      () -> ss2.onSuccess(1)
              );
  
              ts.assertResult(1, 1);
          }
      }
  
      @Test
      public void successCompleteRace() {
          for (int i = 0; i < TestHelper.RACE_DEFAULT_LOOPS; i++) {
              MaybeSubject<Integer> ss1 = MaybeSubject.create();
              MaybeSubject<Integer> ss2 = MaybeSubject.create();
  
              TestSubscriber<Integer> ts = Flowable.just(ss1, ss2).flatMapMaybe(v -> v)
              .test();
  
              TestHelper.race(
                      () -> ss1.onSuccess(1),
                      () -> ss2.onComplete()
              );
  
              ts.assertResult(1);
          }
      }
  
      @Test
      public void successShortcut() {
          MaybeSubject<Integer> ss1 = MaybeSubject.create();
  
          TestSubscriber<Integer> ts = Flowable.just(ss1).hide().flatMapMaybe(v -> v)
          .test();
  
          ss1.onSuccess(1);
  
          ts.assertResult(1);
      }
  }
  