| 1 | // Copyright 2013 The Chromium Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | package org.chromium.base; |
| 6 | |
| 7 | import android.test.InstrumentationTestCase; |
| 8 | import android.test.suitebuilder.annotation.SmallTest; |
| 9 | |
| 10 | import org.chromium.base.test.util.Feature; |
| 11 | |
| 12 | import java.lang.Iterable; |
| 13 | import java.util.Iterator; |
| 14 | import java.util.NoSuchElementException; |
| 15 | |
| 16 | /** |
| 17 | * Tests for (@link ObserverList}. |
| 18 | */ |
| 19 | public class ObserverListTest extends InstrumentationTestCase { |
| 20 | interface Observer { |
| 21 | void observe(int x); |
| 22 | } |
| 23 | |
| 24 | private static class Foo implements Observer { |
| 25 | private final int mScalar; |
| 26 | private int mTotal = 0; |
| 27 | |
| 28 | Foo(int scalar) { |
| 29 | mScalar = scalar; |
| 30 | } |
| 31 | |
| 32 | @Override |
| 33 | public void observe(int x) { |
| 34 | mTotal += x * mScalar; |
| 35 | } |
| 36 | } |
| 37 | |
| 38 | /** |
| 39 | * An observer which add a given Observer object to the list when observe is called. |
| 40 | */ |
| 41 | private static class FooAdder implements Observer { |
| 42 | private final ObserverList<Observer> mList; |
| 43 | private final Observer mLucky; |
| 44 | |
| 45 | FooAdder(ObserverList<Observer> list, Observer oblivious) { |
| 46 | mList = list; |
| 47 | mLucky = oblivious; |
| 48 | } |
| 49 | |
| 50 | @Override |
| 51 | public void observe(int x) { |
| 52 | mList.addObserver(mLucky); |
| 53 | } |
| 54 | } |
| 55 | |
| 56 | /** |
| 57 | * An observer which removes a given Observer object from the list when observe is called. |
| 58 | */ |
| 59 | private static class FooRemover implements Observer { |
| 60 | private final ObserverList<Observer> mList; |
| 61 | private final Observer mDoomed; |
| 62 | |
| 63 | FooRemover(ObserverList<Observer> list, Observer innocent) { |
| 64 | mList = list; |
| 65 | mDoomed = innocent; |
| 66 | } |
| 67 | |
| 68 | @Override |
| 69 | public void observe(int x) { |
| 70 | mList.removeObserver(mDoomed); |
| 71 | } |
| 72 | } |
| 73 | |
| 74 | private static <T> int getSizeOfIterable(Iterable<T> iterable) { |
| 75 | int num = 0; |
| 76 | for (T el : iterable) |
| 77 | num++; |
| 78 | return num; |
| 79 | } |
| 80 | |
| 81 | @SmallTest |
| 82 | @Feature({"Android-AppBase"}) |
| 83 | public void testRemoveWhileIteration() { |
| 84 | ObserverList<Observer> observerList = new ObserverList<Observer>(); |
| 85 | Foo a = new Foo(1); |
| 86 | Foo b = new Foo(-1); |
| 87 | Foo c = new Foo(1); |
| 88 | Foo d = new Foo(-1); |
| 89 | Foo e = new Foo(-1); |
| 90 | FooRemover evil = new FooRemover(observerList, c); |
| 91 | |
| 92 | observerList.addObserver(a); |
| 93 | observerList.addObserver(b); |
| 94 | |
| 95 | for (Observer obs : observerList) |
| 96 | obs.observe(10); |
| 97 | |
| 98 | // Removing an observer not in the list should do nothing. |
| 99 | observerList.removeObserver(e); |
| 100 | |
| 101 | observerList.addObserver(evil); |
| 102 | observerList.addObserver(c); |
| 103 | observerList.addObserver(d); |
| 104 | |
| 105 | for (Observer obs : observerList) |
| 106 | obs.observe(10); |
| 107 | |
| 108 | // observe should be called twice on a. |
| 109 | assertEquals(20, a.mTotal); |
| 110 | // observe should be called twice on b. |
| 111 | assertEquals(-20, b.mTotal); |
| 112 | // evil removed c from the observerList before it got any callbacks. |
| 113 | assertEquals(0, c.mTotal); |
| 114 | // observe should be called once on d. |
| 115 | assertEquals(-10, d.mTotal); |
| 116 | // e was never added to the list, observe should not be called. |
| 117 | assertEquals(0, e.mTotal); |
| 118 | } |
| 119 | |
| 120 | @SmallTest |
| 121 | @Feature({"Android-AppBase"}) |
| 122 | public void testAddWhileIteration() { |
| 123 | ObserverList<Observer> observerList = new ObserverList<Observer>(); |
| 124 | Foo a = new Foo(1); |
| 125 | Foo b = new Foo(-1); |
| 126 | Foo c = new Foo(1); |
| 127 | FooAdder evil = new FooAdder(observerList, c); |
| 128 | |
| 129 | observerList.addObserver(evil); |
| 130 | observerList.addObserver(a); |
| 131 | observerList.addObserver(b); |
| 132 | |
| 133 | for (Observer obs : observerList) |
| 134 | obs.observe(10); |
| 135 | |
| 136 | assertTrue(observerList.hasObserver(c)); |
| 137 | assertEquals(10, a.mTotal); |
| 138 | assertEquals(-10, b.mTotal); |
| 139 | assertEquals(0, c.mTotal); |
| 140 | } |
| 141 | |
| 142 | @SmallTest |
| 143 | @Feature({"Android-AppBase"}) |
| 144 | public void testIterator() { |
| 145 | ObserverList<Integer> observerList = new ObserverList<Integer>(); |
| 146 | observerList.addObserver(5); |
| 147 | observerList.addObserver(10); |
| 148 | observerList.addObserver(15); |
| 149 | assertEquals(3, getSizeOfIterable(observerList)); |
| 150 | |
| 151 | observerList.removeObserver(10); |
| 152 | assertEquals(2, getSizeOfIterable(observerList)); |
| 153 | |
| 154 | Iterator<Integer> it = observerList.iterator(); |
| 155 | assertTrue(it.hasNext()); |
| 156 | assertTrue(5 == it.next()); |
| 157 | assertTrue(it.hasNext()); |
| 158 | assertTrue(15 == it.next()); |
| 159 | assertFalse(it.hasNext()); |
| 160 | |
| 161 | boolean removeExceptionThrown = false; |
| 162 | try { |
| 163 | it.remove(); |
| 164 | fail("Expecting UnsupportedOperationException to be thrown here."); |
| 165 | } catch (UnsupportedOperationException e) { |
| 166 | removeExceptionThrown = true; |
| 167 | } |
| 168 | assertTrue(removeExceptionThrown); |
| 169 | assertEquals(2, getSizeOfIterable(observerList)); |
| 170 | |
| 171 | boolean noElementExceptionThrown = false; |
| 172 | try { |
| 173 | it.next(); |
| 174 | fail("Expecting NoSuchElementException to be thrown here."); |
| 175 | } catch (NoSuchElementException e) { |
| 176 | noElementExceptionThrown = true; |
| 177 | } |
| 178 | assertTrue(noElementExceptionThrown); |
| 179 | } |
| 180 | } |