1/*
2 * Copyright (C) 2010 The Android Open Source Project
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
17package libcore.libcore.util;
18
19import java.lang.ref.Reference;
20import java.lang.ref.WeakReference;
21import java.util.ArrayList;
22import java.util.Arrays;
23import java.util.Collections;
24import java.util.Iterator;
25import java.util.List;
26import junit.framework.TestCase;
27
28import libcore.util.CollectionUtils;
29
30public final class CollectionUtilsTest extends TestCase {
31
32    public void testDereferenceIterable() {
33        List<Reference<String>> refs = new ArrayList<Reference<String>>();
34        refs.add(newLiteralReference("a"));
35        refs.add(newLiteralReference("b"));
36        refs.add(newLiteralReference("c"));
37        refs.add(newLiteralReference("d"));
38        refs.add(newLiteralReference("e"));
39
40        Iterable<String> strings = CollectionUtils.dereferenceIterable(refs, true);
41        assertEquals(Arrays.<String>asList("a", "b", "c", "d", "e"), toList(strings));
42
43        refs.get(1).clear(); // b
44        assertEquals(Arrays.<String>asList("a", "c", "d", "e"), toList(strings));
45        assertEquals(4, refs.size());
46
47        Iterator<String> i = strings.iterator();
48        assertEquals("a", i.next());
49        i.remove();
50        assertEquals(3, refs.size());
51        assertEquals("c", i.next());
52        assertEquals("d", i.next());
53        assertTrue(i.hasNext());
54        try {
55            i.remove();
56            fail("Expected hasNext() to make remove() impossible.");
57        } catch (IllegalStateException expected) {
58        }
59        assertEquals("e", i.next());
60        i.remove();
61        assertEquals(2, refs.size());
62        assertFalse(i.hasNext());
63
64        refs.get(0).clear(); // c
65        refs.get(1).clear(); // d
66        assertEquals(Arrays.<String>asList(), toList(strings));
67    }
68
69    private <T> List<T> toList(Iterable<T> iterable) {
70        List<T> result = new ArrayList<T>();
71        for (T t : iterable) {
72            result.add(t);
73        }
74        return result;
75    }
76
77    public void testRemoveDuplicatesOnEmptyCollection() {
78        List<String> list = new ArrayList<String>();
79        CollectionUtils.removeDuplicates(list, String.CASE_INSENSITIVE_ORDER);
80        assertTrue(list.isEmpty());
81    }
82
83    public void testRemoveDuplicatesOnSingletonCollection() {
84        List<String> list = Arrays.asList("A");
85        CollectionUtils.removeDuplicates(list, String.CASE_INSENSITIVE_ORDER);
86        assertEquals(Collections.singletonList("A"), list);
87    }
88
89    public void testRemoveDuplicates() {
90        List<String> list = new ArrayList<String>();
91        list.add("A");
92        list.add("A");
93        list.add("A");
94        list.add("B");
95        list.add("C");
96        list.add("C");
97        list.add("C");
98        CollectionUtils.removeDuplicates(list, String.CASE_INSENSITIVE_ORDER);
99        assertEquals(Arrays.asList("A", "B", "C"), list);
100    }
101
102    /**
103     * A reference that must be manually cleared.
104     */
105    public Reference<String> newLiteralReference(String s) {
106        return new WeakReference<String>(s);
107    }
108}
109