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.NoSuchElementException;
  
  import org.junit.Test;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.exceptions.TestException;
  import io.reactivex.rxjava3.observers.TestObserver;
  import io.reactivex.rxjava3.subjects.MaybeSubject;
  
  public class SingleFromMaybeTest extends RxJavaTest {
  
      @Test
      public void success() {
          Single.fromMaybe(Maybe.just(1).hide())
          .test()
          .assertResult(1);
      }
  
      @Test
      public void empty() {
          Single.fromMaybe(Maybe.empty().hide())
          .test()
          .assertFailure(NoSuchElementException.class);
      }
  
      @Test
      public void emptyDefault() {
          Single.fromMaybe(Maybe.empty().hide(), 1)
          .test()
          .assertResult(1);
      }
  
      @Test
      public void error() {
          Single.fromMaybe(Maybe.error(new TestException()).hide())
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void cancelComposes() {
          MaybeSubject<Integer> ms = MaybeSubject.create();
  
          TestObserver<Integer> to = Single.fromMaybe(ms)
          .test();
  
          to.assertEmpty();
  
          assertTrue(ms.hasObservers());
  
          to.dispose();
  
          assertFalse(ms.hasObservers());
      }
  }
  