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      1 /*
      2  * Copyright 2017, OpenCensus Authors
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *     http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package io.opencensus.implcore.trace.internal;
     18 
     19 import static com.google.common.truth.Truth.assertThat;
     20 
     21 import io.opencensus.implcore.trace.internal.ConcurrentIntrusiveList.Element;
     22 import javax.annotation.Nullable;
     23 import org.junit.Rule;
     24 import org.junit.Test;
     25 import org.junit.rules.ExpectedException;
     26 import org.junit.runner.RunWith;
     27 import org.junit.runners.JUnit4;
     28 
     29 /** Unit tests for {@link ConcurrentIntrusiveList}. */
     30 @RunWith(JUnit4.class)
     31 public class ConcurrentIntrusiveListTest {
     32   private final ConcurrentIntrusiveList<FakeElement> intrusiveList =
     33       new ConcurrentIntrusiveList<FakeElement>();
     34   @Rule public final ExpectedException exception = ExpectedException.none();
     35 
     36   @Test
     37   public void emptyList() {
     38     assertThat(intrusiveList.size()).isEqualTo(0);
     39     assertThat(intrusiveList.getAll().isEmpty()).isTrue();
     40   }
     41 
     42   @Test
     43   public void addRemoveAdd_SameElement() {
     44     FakeElement element = new FakeElement();
     45     intrusiveList.addElement(element);
     46     assertThat(intrusiveList.size()).isEqualTo(1);
     47     intrusiveList.removeElement(element);
     48     assertThat(intrusiveList.size()).isEqualTo(0);
     49     intrusiveList.addElement(element);
     50     assertThat(intrusiveList.size()).isEqualTo(1);
     51   }
     52 
     53   @Test
     54   public void addAndRemoveElements() {
     55     FakeElement element1 = new FakeElement();
     56     FakeElement element2 = new FakeElement();
     57     FakeElement element3 = new FakeElement();
     58     intrusiveList.addElement(element1);
     59     intrusiveList.addElement(element2);
     60     intrusiveList.addElement(element3);
     61     assertThat(intrusiveList.size()).isEqualTo(3);
     62     assertThat(intrusiveList.getAll()).containsExactly(element3, element2, element1).inOrder();
     63     // Remove element from the middle of the list.
     64     intrusiveList.removeElement(element2);
     65     assertThat(intrusiveList.size()).isEqualTo(2);
     66     assertThat(intrusiveList.getAll()).containsExactly(element3, element1).inOrder();
     67     // Remove element from the tail of the list.
     68     intrusiveList.removeElement(element1);
     69     assertThat(intrusiveList.size()).isEqualTo(1);
     70     assertThat(intrusiveList.getAll().contains(element3)).isTrue();
     71     intrusiveList.addElement(element1);
     72     assertThat(intrusiveList.size()).isEqualTo(2);
     73     assertThat(intrusiveList.getAll()).containsExactly(element1, element3).inOrder();
     74     // Remove element from the head of the list when there are other elements after.
     75     intrusiveList.removeElement(element1);
     76     assertThat(intrusiveList.size()).isEqualTo(1);
     77     assertThat(intrusiveList.getAll().contains(element3)).isTrue();
     78     // Remove element from the head of the list when no more other elements in the list.
     79     intrusiveList.removeElement(element3);
     80     assertThat(intrusiveList.size()).isEqualTo(0);
     81     assertThat(intrusiveList.getAll().isEmpty()).isTrue();
     82   }
     83 
     84   @Test
     85   public void addAlreadyAddedElement() {
     86     FakeElement element = new FakeElement();
     87     intrusiveList.addElement(element);
     88     exception.expect(IllegalArgumentException.class);
     89     intrusiveList.addElement(element);
     90   }
     91 
     92   @Test
     93   public void removeNotAddedElement() {
     94     FakeElement element = new FakeElement();
     95     exception.expect(IllegalArgumentException.class);
     96     intrusiveList.removeElement(element);
     97   }
     98 
     99   private static final class FakeElement implements Element<FakeElement> {
    100     @Nullable private FakeElement next = null;
    101     @Nullable private FakeElement prev = null;
    102 
    103     @Override
    104     public FakeElement getNext() {
    105       return next;
    106     }
    107 
    108     @Override
    109     public void setNext(FakeElement element) {
    110       next = element;
    111     }
    112 
    113     @Override
    114     public FakeElement getPrev() {
    115       return prev;
    116     }
    117 
    118     @Override
    119     public void setPrev(FakeElement element) {
    120       prev = element;
    121     }
    122   }
    123 }
    124