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.mockito.ArgumentMatchers.any;
  import static org.mockito.Mockito.*;
  
  import org.junit.Test;
  import org.reactivestreams.Subscriber;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.exceptions.TestException;
  import io.reactivex.rxjava3.functions.Supplier;
  import io.reactivex.rxjava3.testsupport.TestHelper;
  
  @SuppressWarnings("unchecked")
  public class FlowableDeferTest extends RxJavaTest {
  
      @Test
      public void defer() throws Throwable {
  
          Supplier<Flowable<String>> factory = mock(Supplier.class);
  
          Flowable<String> firstObservable = Flowable.just("one", "two");
          Flowable<String> secondObservable = Flowable.just("three", "four");
          when(factory.get()).thenReturn(firstObservable, secondObservable);
  
          Flowable<String> deferred = Flowable.defer(factory);
  
          verifyNoInteractions(factory);
  
          Subscriber<String> firstSubscriber = TestHelper.mockSubscriber();
          deferred.subscribe(firstSubscriber);
  
          verify(factory, times(1)).get();
          verify(firstSubscriber, times(1)).onNext("one");
          verify(firstSubscriber, times(1)).onNext("two");
          verify(firstSubscriber, times(0)).onNext("three");
          verify(firstSubscriber, times(0)).onNext("four");
          verify(firstSubscriber, times(1)).onComplete();
  
          Subscriber<String> secondSubscriber = TestHelper.mockSubscriber();
          deferred.subscribe(secondSubscriber);
  
          verify(factory, times(2)).get();
          verify(secondSubscriber, times(0)).onNext("one");
          verify(secondSubscriber, times(0)).onNext("two");
          verify(secondSubscriber, times(1)).onNext("three");
          verify(secondSubscriber, times(1)).onNext("four");
          verify(secondSubscriber, times(1)).onComplete();
  
      }
  
      @Test
      public void deferFunctionThrows() throws Throwable {
          Supplier<Flowable<String>> factory = mock(Supplier.class);
  
          when(factory.get()).thenThrow(new TestException());
  
          Flowable<String> result = Flowable.defer(factory);
  
          Subscriber<String> subscriber = TestHelper.mockSubscriber();
  
          result.subscribe(subscriber);
  
          verify(subscriber).onError(any(TestException.class));
          verify(subscriber, never()).onNext(any(String.class));
          verify(subscriber, never()).onComplete();
      }
  }
  