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 io.reactivex.rxjava3.disposables.Disposable;
  import org.junit.Test;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.exceptions.*;
  import io.reactivex.rxjava3.functions.*;
  import io.reactivex.rxjava3.internal.functions.Functions;
  import io.reactivex.rxjava3.internal.operators.observable.ObservableMapNotification.MapNotificationObserver;
  import io.reactivex.rxjava3.observers.TestObserver;
  import io.reactivex.rxjava3.testsupport.*;
  
  public class ObservableMapNotificationTest extends RxJavaTest {
      @Test
      public void just() {
          TestObserver<Object> to = new TestObserver<>();
          Observable.just(1)
          .flatMap(
                  new Function<Integer, Observable<Object>>() {
                      @Override
                      public Observable<Object> apply(Integer item) {
                          return Observable.just((Object)(item + 1));
                      }
                  },
                  new Function<Throwable, Observable<Object>>() {
                      @Override
                      public Observable<Object> apply(Throwable e) {
                          return Observable.error(e);
                      }
                  },
                  new Supplier<Observable<Object>>() {
                      @Override
                      public Observable<Object> get() {
                          return Observable.never();
                      }
                  }
          ).subscribe(to);
  
          to.assertNoErrors();
          to.assertNotComplete();
          to.assertValue(2);
      }
  
      @Test
      public void dispose() {
          TestHelper.checkDisposed(new Observable<Integer>() {
              @SuppressWarnings({ "rawtypes", "unchecked" })
              @Override
              protected void subscribeActual(Observer<? super Integer> observer) {
                  MapNotificationObserver mn = new MapNotificationObserver(
                          observer,
                          Functions.justFunction(Observable.just(1)),
                          Functions.justFunction(Observable.just(2)),
                          Functions.justSupplier(Observable.just(3))
                  );
                  mn.onSubscribe(Disposable.empty());
              }
          });
      }
  
      @Test
      public void doubleOnSubscribe() {
          TestHelper.checkDoubleOnSubscribeObservable(new Function<Observable<Object>, ObservableSource<Integer>>() {
              @Override
              public ObservableSource<Integer> apply(Observable<Object> o) throws Exception {
                  return o.flatMap(
                          Functions.justFunction(Observable.just(1)),
                          Functions.justFunction(Observable.just(2)),
                          Functions.justSupplier(Observable.just(3))
                  );
              }
          });
      }
  
      @Test
      public void onErrorCrash() {
          TestObserverEx<Integer> to = Observable.<Integer>error(new TestException("Outer"))
          .flatMap(Functions.justFunction(Observable.just(1)),
                  new Function<Throwable, Observable<Integer>>() {
                      @Override
                      public Observable<Integer> apply(Throwable t) throws Exception {
                          throw new TestException("Inner");
                      }
                  },
                  Functions.justSupplier(Observable.just(3)))
          .to(TestHelper.<Integer>testConsumer())
          .assertFailure(CompositeException.class);
  
          TestHelper.assertError(to, 0, TestException.class, "Outer");
          TestHelper.assertError(to, 1, TestException.class, "Inner");
      }
  }
  