FlowableDistinctUntilChangedTest.java

/**
 * Copyright 2016 Netflix, Inc.
 * 
 * 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.internal.operators.flowable;

import static org.mockito.Matchers.*;
import static org.mockito.Mockito.*;

import java.util.concurrent.atomic.AtomicBoolean;

import org.junit.*;
import org.mockito.InOrder;
import org.reactivestreams.Subscriber;

import io.reactivex.*;
import io.reactivex.exceptions.TestException;
import io.reactivex.functions.*;
import io.reactivex.internal.fuseable.QueueSubscription;
import io.reactivex.subscribers.*;

public class FlowableDistinctUntilChangedTest {

    Subscriber<String> w;
    Subscriber<String> w2;

    // nulls lead to exceptions
    final Function<String, String> TO_UPPER_WITH_EXCEPTION = new Function<String, String>() {
        @Override
        public String apply(String s) {
            if (s.equals("x")) {
                return "xx";
            }
            return s.toUpperCase();
        }
    };

    @Before
    public void before() {
        w = TestHelper.mockSubscriber();
        w2 = TestHelper.mockSubscriber();
    }

    @Test
    public void testDistinctUntilChangedOfNone() {
        Flowable<String> src = Flowable.empty();
        src.distinctUntilChanged().subscribe(w);

        verify(w, never()).onNext(anyString());
        verify(w, never()).onError(any(Throwable.class));
        verify(w, times(1)).onComplete();
    }

    @Test
    public void testDistinctUntilChangedOfNoneWithKeySelector() {
        Flowable<String> src = Flowable.empty();
        src.distinctUntilChanged(TO_UPPER_WITH_EXCEPTION).subscribe(w);

        verify(w, never()).onNext(anyString());
        verify(w, never()).onError(any(Throwable.class));
        verify(w, times(1)).onComplete();
    }

    @Test
    public void testDistinctUntilChangedOfNormalSource() {
        Flowable<String> src = Flowable.just("a", "b", "c", "c", "c", "b", "b", "a", "e");
        src.distinctUntilChanged().subscribe(w);

        InOrder inOrder = inOrder(w);
        inOrder.verify(w, times(1)).onNext("a");
        inOrder.verify(w, times(1)).onNext("b");
        inOrder.verify(w, times(1)).onNext("c");
        inOrder.verify(w, times(1)).onNext("b");
        inOrder.verify(w, times(1)).onNext("a");
        inOrder.verify(w, times(1)).onNext("e");
        inOrder.verify(w, times(1)).onComplete();
        inOrder.verify(w, never()).onNext(anyString());
        verify(w, never()).onError(any(Throwable.class));
    }

    @Test
    public void testDistinctUntilChangedOfNormalSourceWithKeySelector() {
        Flowable<String> src = Flowable.just("a", "b", "c", "C", "c", "B", "b", "a", "e");
        src.distinctUntilChanged(TO_UPPER_WITH_EXCEPTION).subscribe(w);

        InOrder inOrder = inOrder(w);
        inOrder.verify(w, times(1)).onNext("a");
        inOrder.verify(w, times(1)).onNext("b");
        inOrder.verify(w, times(1)).onNext("c");
        inOrder.verify(w, times(1)).onNext("B");
        inOrder.verify(w, times(1)).onNext("a");
        inOrder.verify(w, times(1)).onNext("e");
        inOrder.verify(w, times(1)).onComplete();
        inOrder.verify(w, never()).onNext(anyString());
        verify(w, never()).onError(any(Throwable.class));
    }

    @Test
    @Ignore("Null values no longer allowed")
    public void testDistinctUntilChangedOfSourceWithNulls() {
        Flowable<String> src = Flowable.just(null, "a", "a", null, null, "b", null, null);
        src.distinctUntilChanged().subscribe(w);

        InOrder inOrder = inOrder(w);
        inOrder.verify(w, times(1)).onNext(null);
        inOrder.verify(w, times(1)).onNext("a");
        inOrder.verify(w, times(1)).onNext(null);
        inOrder.verify(w, times(1)).onNext("b");
        inOrder.verify(w, times(1)).onNext(null);
        inOrder.verify(w, times(1)).onComplete();
        inOrder.verify(w, never()).onNext(anyString());
        verify(w, never()).onError(any(Throwable.class));
    }

    @Test
    @Ignore("Null values no longer allowed")
    public void testDistinctUntilChangedOfSourceWithExceptionsFromKeySelector() {
        Flowable<String> src = Flowable.just("a", "b", null, "c");
        src.distinctUntilChanged(TO_UPPER_WITH_EXCEPTION).subscribe(w);

        InOrder inOrder = inOrder(w);
        inOrder.verify(w, times(1)).onNext("a");
        inOrder.verify(w, times(1)).onNext("b");
        verify(w, times(1)).onError(any(NullPointerException.class));
        inOrder.verify(w, never()).onNext(anyString());
        inOrder.verify(w, never()).onComplete();
    }
    
    @Test
    public void directComparer() {
        Flowable.fromArray(1, 2, 2, 3, 2, 4, 1, 1, 2)
        .distinctUntilChanged(new BiPredicate<Integer, Integer>() {
            @Override
            public boolean test(Integer a, Integer b) {
                return a.equals(b);
            }
        })
        .test()
        .assertResult(1, 2, 3, 2, 4, 1, 2);
    }
    
    @Test
    public void directComparerConditional() {
        Flowable.fromArray(1, 2, 2, 3, 2, 4, 1, 1, 2)
        .distinctUntilChanged(new BiPredicate<Integer, Integer>() {
            @Override
            public boolean test(Integer a, Integer b) {
                return a.equals(b);
            }
        })
        .filter(new Predicate<Integer>() {
            @Override
            public boolean test(Integer v) {
                return true;
            }
        })
        .test()
        .assertResult(1, 2, 3, 2, 4, 1, 2);
    }
    
    @Test
    public void directComparerFused() {
        Flowable.fromArray(1, 2, 2, 3, 2, 4, 1, 1, 2)
        .distinctUntilChanged(new BiPredicate<Integer, Integer>() {
            @Override
            public boolean test(Integer a, Integer b) {
                return a.equals(b);
            }
        })
        .to(SubscriberFusion.<Integer>test(Long.MAX_VALUE, QueueSubscription.ANY, false))
        .assertOf(SubscriberFusion.<Integer>assertFuseable())
        .assertOf(SubscriberFusion.<Integer>assertFusionMode(QueueSubscription.SYNC))
        .assertResult(1, 2, 3, 2, 4, 1, 2);
    }
    
    @Test
    public void directComparerConditionalFused() {
        Flowable.fromArray(1, 2, 2, 3, 2, 4, 1, 1, 2)
        .distinctUntilChanged(new BiPredicate<Integer, Integer>() {
            @Override
            public boolean test(Integer a, Integer b) {
                return a.equals(b);
            }
        })
        .filter(new Predicate<Integer>() {
            @Override
            public boolean test(Integer v) {
                return true;
            }
        })
        .to(SubscriberFusion.<Integer>test(Long.MAX_VALUE, QueueSubscription.ANY, false))
        .assertOf(SubscriberFusion.<Integer>assertFuseable())
        .assertOf(SubscriberFusion.<Integer>assertFusionMode(QueueSubscription.SYNC))
        .assertResult(1, 2, 3, 2, 4, 1, 2);
    }
    
    private final static Function<String, String> THROWS_NON_FATAL = new Function<String, String>() {
        @Override
        public String apply(String s) {
            throw new RuntimeException();
        }
    };
    
    @Test
    public void testDistinctUntilChangedWhenNonFatalExceptionThrownByKeySelectorIsNotReportedByUpstream() {
        Flowable<String> src = Flowable.just("a", "b", "null", "c");
        final AtomicBoolean errorOccurred = new AtomicBoolean(false);
        src
          .doOnError(new Consumer<Throwable>() {
                @Override
                public void accept(Throwable t) {
                    errorOccurred.set(true);
                }
            })
          .distinctUntilChanged(THROWS_NON_FATAL)
          .subscribe(w);
        Assert.assertFalse(errorOccurred.get());
    }
    
    @Test
    public void customComparator() {
        Flowable<String> source = Flowable.just("a", "b", "B", "A","a", "C");
        
        TestSubscriber<String> ts = TestSubscriber.create();
        
        source.distinctUntilChanged(new BiPredicate<String, String>() {
            @Override
            public boolean test(String a, String b) {
                return a.compareToIgnoreCase(b) == 0;
            }
        })
        .subscribe(ts);
        
        ts.assertValues("a", "b", "A", "C");
        ts.assertNoErrors();
        ts.assertComplete();
    }

    @Test
    public void customComparatorThrows() {
        Flowable<String> source = Flowable.just("a", "b", "B", "A","a", "C");
        
        TestSubscriber<String> ts = TestSubscriber.create();
        
        source.distinctUntilChanged(new BiPredicate<String, String>() {
            @Override
            public boolean test(String a, String b) {
                throw new TestException();
            }
        })
        .subscribe(ts);
        
        ts.assertValue("a");
        ts.assertNotComplete();
        ts.assertError(TestException.class);
    }
}