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 static org.mockito.ArgumentMatchers.any;
  import static org.mockito.Mockito.*;
  
  import java.util.NoSuchElementException;
  
  import org.junit.Test;
  import org.mockito.InOrder;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.exceptions.TestException;
  import io.reactivex.rxjava3.functions.*;
  import io.reactivex.rxjava3.testsupport.TestHelper;
  
  public class FlowableLastTest extends RxJavaTest {
  
      @Test
      public void lastWithElements() {
          Maybe<Integer> last = Flowable.just(1, 2, 3).lastElement();
          assertEquals(3, last.blockingGet().intValue());
      }
  
      @Test
      public void lastWithNoElements() {
          Maybe<?> last = Flowable.empty().lastElement();
          assertNull(last.blockingGet());
      }
  
      @Test
      public void lastMultiSubscribe() {
          Maybe<Integer> last = Flowable.just(1, 2, 3).lastElement();
          assertEquals(3, last.blockingGet().intValue());
          assertEquals(3, last.blockingGet().intValue());
      }
  
      @Test
      public void lastViaFlowable() {
          Flowable.just(1, 2, 3).lastElement();
      }
  
      @Test
      public void last() {
          Maybe<Integer> maybe = Flowable.just(1, 2, 3).lastElement();
  
          MaybeObserver<Integer> observer = TestHelper.mockMaybeObserver();
          maybe.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer, times(1)).onSuccess(3);
  //        inOrder.verify(observer, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void lastWithOneElement() {
          Maybe<Integer> maybe = Flowable.just(1).lastElement();
  
          MaybeObserver<Integer> observer = TestHelper.mockMaybeObserver();
          maybe.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer, times(1)).onSuccess(1);
  //        inOrder.verify(observer, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void lastWithEmpty() {
          Maybe<Integer> maybe = Flowable.<Integer> empty().lastElement();
  
          MaybeObserver<Integer> observer = TestHelper.mockMaybeObserver();
          maybe.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer).onComplete();
          inOrder.verify(observer, never()).onError(any(Throwable.class));
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void lastWithPredicate() {
          Maybe<Integer> maybe = Flowable.just(1, 2, 3, 4, 5, 6)
                  .filter(new Predicate<Integer>() {
  
                      @Override
                      public boolean test(Integer t1) {
                          return t1 % 2 == 0;
                      }
                  })
                  .lastElement();
  
          MaybeObserver<Integer> observer = TestHelper.mockMaybeObserver();
          maybe.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer, times(1)).onSuccess(6);
  //        inOrder.verify(observer, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void lastWithPredicateAndOneElement() {
          Maybe<Integer> maybe = Flowable.just(1, 2)
              .filter(
                  new Predicate<Integer>() {
  
                      @Override
                      public boolean test(Integer t1) {
                          return t1 % 2 == 0;
                      }
                  })
              .lastElement();
  
          MaybeObserver<Integer> observer = TestHelper.mockMaybeObserver();
          maybe.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer, times(1)).onSuccess(2);
  //        inOrder.verify(observer, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void lastWithPredicateAndEmpty() {
          Maybe<Integer> maybe = Flowable.just(1)
              .filter(
                  new Predicate<Integer>() {
  
                      @Override
                      public boolean test(Integer t1) {
                          return t1 % 2 == 0;
                      }
                  }).lastElement();
  
          MaybeObserver<Integer> observer = TestHelper.mockMaybeObserver();
          maybe.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer).onComplete();
          inOrder.verify(observer, never()).onError(any(Throwable.class));
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void lastOrDefault() {
          Single<Integer> single = Flowable.just(1, 2, 3)
                  .last(4);
  
          SingleObserver<Integer> observer = TestHelper.mockSingleObserver();
          single.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer, times(1)).onSuccess(3);
  //        inOrder.verify(observer, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void lastOrDefaultWithOneElement() {
          Single<Integer> single = Flowable.just(1).last(2);
  
          SingleObserver<Integer> observer = TestHelper.mockSingleObserver();
          single.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer, times(1)).onSuccess(1);
  //        inOrder.verify(observer, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void lastOrDefaultWithEmpty() {
          Single<Integer> single = Flowable.<Integer> empty()
                  .last(1);
  
          SingleObserver<Integer> observer = TestHelper.mockSingleObserver();
          single.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer, times(1)).onSuccess(1);
  //        inOrder.verify(observer, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void lastOrDefaultWithPredicate() {
          Single<Integer> single = Flowable.just(1, 2, 3, 4, 5, 6)
                  .filter(new Predicate<Integer>() {
  
                      @Override
                      public boolean test(Integer t1) {
                          return t1 % 2 == 0;
                      }
                  })
                  .last(8);
  
          SingleObserver<Integer> observer = TestHelper.mockSingleObserver();
          single.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer, times(1)).onSuccess(6);
  //        inOrder.verify(observer, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void lastOrDefaultWithPredicateAndOneElement() {
          Single<Integer> single = Flowable.just(1, 2)
                  .filter(new Predicate<Integer>() {
  
                      @Override
                      public boolean test(Integer t1) {
                          return t1 % 2 == 0;
                      }
                  })
                  .last(4);
  
          SingleObserver<Integer> observer = TestHelper.mockSingleObserver();
          single.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer, times(1)).onSuccess(2);
  //        inOrder.verify(observer, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void lastOrDefaultWithPredicateAndEmpty() {
          Single<Integer> single = Flowable.just(1)
                  .filter(
                  new Predicate<Integer>() {
  
                      @Override
                      public boolean test(Integer t1) {
                          return t1 % 2 == 0;
                      }
                  })
                  .last(2);
  
          SingleObserver<Integer> observer = TestHelper.mockSingleObserver();
          single.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          inOrder.verify(observer, times(1)).onSuccess(2);
  //        inOrder.verify(observer, times(1)).onComplete();
          inOrder.verifyNoMoreInteractions();
      }
  
      @Test
      public void lastOrErrorNoElement() {
          Flowable.empty()
              .lastOrError()
              .test()
              .assertNoValues()
              .assertError(NoSuchElementException.class);
      }
  
      @Test
      public void lastOrErrorOneElement() {
          Flowable.just(1)
              .lastOrError()
              .test()
              .assertNoErrors()
              .assertValue(1);
      }
  
      @Test
      public void lastOrErrorMultipleElements() {
          Flowable.just(1, 2, 3)
              .lastOrError()
              .test()
              .assertNoErrors()
              .assertValue(3);
      }
  
      @Test
      public void lastOrErrorError() {
          Flowable.error(new RuntimeException("error"))
              .lastOrError()
              .to(TestHelper.testConsumer())
              .assertNoValues()
              .assertErrorMessage("error")
              .assertError(RuntimeException.class);
      }
  
      @Test
      public void dispose() {
          TestHelper.checkDisposed(Flowable.never().lastElement().toFlowable());
          TestHelper.checkDisposed(Flowable.never().lastElement());
  
          TestHelper.checkDisposed(Flowable.just(1).lastOrError().toFlowable());
          TestHelper.checkDisposed(Flowable.just(1).lastOrError());
  
          TestHelper.checkDisposed(Flowable.just(1).last(2).toFlowable());
          TestHelper.checkDisposed(Flowable.just(1).last(2));
      }
  
      @Test
      public void doubleOnSubscribe() {
          TestHelper.checkDoubleOnSubscribeFlowableToMaybe(new Function<Flowable<Object>, MaybeSource<Object>>() {
              @Override
              public MaybeSource<Object> apply(Flowable<Object> f) throws Exception {
                  return f.lastElement();
              }
          });
          TestHelper.checkDoubleOnSubscribeFlowable(new Function<Flowable<Object>, Flowable<Object>>() {
              @Override
              public Flowable<Object> apply(Flowable<Object> f) throws Exception {
                  return f.lastElement().toFlowable();
              }
          });
  
          TestHelper.checkDoubleOnSubscribeFlowableToSingle(new Function<Flowable<Object>, SingleSource<Object>>() {
              @Override
              public SingleSource<Object> apply(Flowable<Object> f) throws Exception {
                  return f.lastOrError();
              }
          });
          TestHelper.checkDoubleOnSubscribeFlowable(new Function<Flowable<Object>, Flowable<Object>>() {
              @Override
              public Flowable<Object> apply(Flowable<Object> f) throws Exception {
                  return f.lastOrError().toFlowable();
              }
          });
  
          TestHelper.checkDoubleOnSubscribeFlowableToSingle(new Function<Flowable<Object>, SingleSource<Object>>() {
              @Override
              public SingleSource<Object> apply(Flowable<Object> f) throws Exception {
                  return f.last(2);
              }
          });
          TestHelper.checkDoubleOnSubscribeFlowable(new Function<Flowable<Object>, Flowable<Object>>() {
              @Override
              public Flowable<Object> apply(Flowable<Object> f) throws Exception {
                  return f.last(2).toFlowable();
              }
          });
      }
  
      @Test
      public void error() {
          Flowable.error(new TestException())
          .lastElement()
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void errorLastOrErrorFlowable() {
          Flowable.error(new TestException())
          .lastOrError()
          .toFlowable()
          .test()
          .assertFailure(TestException.class);
      }
  
      @Test
      public void emptyLastOrErrorFlowable() {
          Flowable.empty()
          .lastOrError()
          .toFlowable()
          .test()
          .assertFailure(NoSuchElementException.class);
      }
  }
  