test/tck/CopyOnWriteArrayListTest.java

/*
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 * Other contributors include Andrew Wright, Jeffrey Hayes,
 * Pat Fisher, Mike Judd.
 */

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import java.util.NoSuchElementException;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.ThreadLocalRandom;

import junit.framework.Test;

public class CopyOnWriteArrayListTest extends JSR166TestCase {

    public static void main(String[] args) {
        main(suite(), args);
    }

    public static Test suite() {
        class Implementation implements CollectionImplementation {
            public Class<?> klazz() { return CopyOnWriteArrayList.class; }
            public List emptyCollection() { return new CopyOnWriteArrayList(); }
            public Object makeElement(int i) { return i; }
            public boolean isConcurrent() { return true; }
            public boolean permitsNulls() { return true; }
        }
        class SubListImplementation extends Implementation {
            public List emptyCollection() {
                List list = super.emptyCollection();
                ThreadLocalRandom rnd = ThreadLocalRandom.current();
                if (rnd.nextBoolean())
                    list.add(makeElement(rnd.nextInt()));
                int i = rnd.nextInt(list.size() + 1);
                return list.subList(i, i);
            }
        }
        return newTestSuite(
                CopyOnWriteArrayListTest.class,
                CollectionTest.testSuite(new Implementation()),
                CollectionTest.testSuite(new SubListImplementation()));
    }

    static CopyOnWriteArrayList<Integer> populatedList(int n) {
        CopyOnWriteArrayList<Integer> list = new CopyOnWriteArrayList<>();
        assertTrue(list.isEmpty());
        for (int i = 0; i < n; i++)
            list.add(i);
        assertEquals(n <= 0, list.isEmpty());
        assertEquals(n, list.size());
        return list;
    }

    static CopyOnWriteArrayList<Integer> populatedList(Integer[] elements) {
        CopyOnWriteArrayList<Integer> list = new CopyOnWriteArrayList<>();
        assertTrue(list.isEmpty());
        for (Integer element : elements)
            list.add(element);
        assertFalse(list.isEmpty());
        assertEquals(elements.length, list.size());
        return list;
    }

    /**
     * a new list is empty
     */
    public void testConstructor() {
        List list = new CopyOnWriteArrayList();
        assertTrue(list.isEmpty());
    }

    /**
     * new list contains all elements of initializing array
     */
    public void testConstructor2() {
        Integer[] elts = new Integer[SIZE];
        for (int i = 0; i < SIZE - 1; ++i)
            elts[i] = i;
        List list = new CopyOnWriteArrayList(elts);
        for (int i = 0; i < SIZE; ++i)
            assertEquals(elts[i], list.get(i));
    }

    /**
     * new list contains all elements of initializing collection
     */
    public void testConstructor3() {
        Integer[] elts = new Integer[SIZE];
        for (int i = 0; i < SIZE - 1; ++i)
            elts[i] = i;
        List list = new CopyOnWriteArrayList(Arrays.asList(elts));
        for (int i = 0; i < SIZE; ++i)
            assertEquals(elts[i], list.get(i));
    }

    /**
     * addAll adds each element from the given collection, including duplicates
     */
    public void testAddAll() {
        List list = populatedList(3);
        assertTrue(list.addAll(Arrays.asList(three, four, five)));
        assertEquals(6, list.size());
        assertTrue(list.addAll(Arrays.asList(three, four, five)));
        assertEquals(9, list.size());
    }

    /**
     * addAllAbsent adds each element from the given collection that did not
     * already exist in the List
     */
    public void testAddAllAbsent() {
        CopyOnWriteArrayList list = populatedList(3);
        // "one" is duplicate and will not be added
        assertEquals(2, list.addAllAbsent(Arrays.asList(three, four, one)));
        assertEquals(5, list.size());
        assertEquals(0, list.addAllAbsent(Arrays.asList(three, four, one)));
        assertEquals(5, list.size());
    }

    /**
     * addIfAbsent will not add the element if it already exists in the list
     */
    public void testAddIfAbsent() {
        CopyOnWriteArrayList list = populatedList(SIZE);
        list.addIfAbsent(one);
        assertEquals(SIZE, list.size());
    }

    /**
     * addIfAbsent adds the element when it does not exist in the list
     */
    public void testAddIfAbsent2() {
        CopyOnWriteArrayList list = populatedList(SIZE);
        list.addIfAbsent(three);
        assertTrue(list.contains(three));
    }

    /**
     * clear removes all elements from the list
     */
    public void testClear() {
        List list = populatedList(SIZE);
        list.clear();
        assertEquals(0, list.size());
    }

    /**
     * Cloned list is equal
     */
    public void testClone() {
        CopyOnWriteArrayList l1 = populatedList(SIZE);
        CopyOnWriteArrayList l2 = (CopyOnWriteArrayList)(l1.clone());
        assertEquals(l1, l2);
        l1.clear();
        assertFalse(l1.equals(l2));
    }

    /**
     * contains is true for added elements
     */
    public void testContains() {
        List list = populatedList(3);
        assertTrue(list.contains(one));
        assertFalse(list.contains(five));
    }

    /**
     * adding at an index places it in the indicated index
     */
    public void testAddIndex() {
        List list = populatedList(3);
        list.add(0, m1);
        assertEquals(4, list.size());
        assertEquals(m1, list.get(0));
        assertEquals(zero, list.get(1));

        list.add(2, m2);
        assertEquals(5, list.size());
        assertEquals(m2, list.get(2));
        assertEquals(two, list.get(4));
    }

    /**
     * lists with same elements are equal and have same hashCode
     */
    public void testEquals() {
        List a = populatedList(3);
        List b = populatedList(3);
        assertTrue(a.equals(b));
        assertTrue(b.equals(a));
        assertTrue(a.containsAll(b));
        assertTrue(b.containsAll(a));
        assertEquals(a.hashCode(), b.hashCode());
        a.add(m1);
        assertFalse(a.equals(b));
        assertFalse(b.equals(a));
        assertTrue(a.containsAll(b));
        assertFalse(b.containsAll(a));
        b.add(m1);
        assertTrue(a.equals(b));
        assertTrue(b.equals(a));
        assertTrue(a.containsAll(b));
        assertTrue(b.containsAll(a));
        assertEquals(a.hashCode(), b.hashCode());

        assertFalse(a.equals(null));
    }

    /**
     * containsAll returns true for collections with subset of elements
     */
    public void testContainsAll() {
        List list = populatedList(3);
        assertTrue(list.containsAll(Arrays.asList()));
        assertTrue(list.containsAll(Arrays.asList(one)));
        assertTrue(list.containsAll(Arrays.asList(one, two)));
        assertFalse(list.containsAll(Arrays.asList(one, two, six)));
        assertFalse(list.containsAll(Arrays.asList(six)));

        try {
            list.containsAll(null);
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * get returns the value at the given index
     */
    public void testGet() {
        List list = populatedList(3);
        assertEquals(0, list.get(0));
    }

    /**
     * indexOf(Object) returns the index of the first occurrence of the
     * specified element in this list, or -1 if this list does not
     * contain the element
     */
    public void testIndexOf() {
        List list = populatedList(3);
        assertEquals(-1, list.indexOf(-42));
        int size = list.size();
        for (int i = 0; i < size; i++) {
            assertEquals(i, list.indexOf(i));
            assertEquals(i, list.subList(0, size).indexOf(i));
            assertEquals(i, list.subList(0, i + 1).indexOf(i));
            assertEquals(-1, list.subList(0, i).indexOf(i));
            assertEquals(0, list.subList(i, size).indexOf(i));
            assertEquals(-1, list.subList(i + 1, size).indexOf(i));
        }

        list.add(1);
        assertEquals(1, list.indexOf(1));
        assertEquals(1, list.subList(0, size + 1).indexOf(1));
        assertEquals(0, list.subList(1, size + 1).indexOf(1));
        assertEquals(size - 2, list.subList(2, size + 1).indexOf(1));
        assertEquals(0, list.subList(size, size + 1).indexOf(1));
        assertEquals(-1, list.subList(size + 1, size + 1).indexOf(1));
    }

    /**
     * indexOf(E, int) returns the index of the first occurrence of the
     * specified element in this list, searching forwards from index,
     * or returns -1 if the element is not found
     */
    public void testIndexOf2() {
        CopyOnWriteArrayList list = populatedList(3);
        int size = list.size();
        assertEquals(-1, list.indexOf(-42, 0));

        // we might expect IOOBE, but spec says otherwise
        assertEquals(-1, list.indexOf(0, size));
        assertEquals(-1, list.indexOf(0, Integer.MAX_VALUE));

        assertThrows(
            IndexOutOfBoundsException.class,
            () -> list.indexOf(0, -1),
            () -> list.indexOf(0, Integer.MIN_VALUE));

        for (int i = 0; i < size; i++) {
            assertEquals(i, list.indexOf(i, 0));
            assertEquals(i, list.indexOf(i, i));
            assertEquals(-1, list.indexOf(i, i + 1));
        }

        list.add(1);
        assertEquals(1, list.indexOf(1, 0));
        assertEquals(1, list.indexOf(1, 1));
        assertEquals(size, list.indexOf(1, 2));
        assertEquals(size, list.indexOf(1, size));
    }

    /**
     * isEmpty returns true when empty, else false
     */
    public void testIsEmpty() {
        List empty = new CopyOnWriteArrayList();
        assertTrue(empty.isEmpty());
        assertTrue(empty.subList(0, 0).isEmpty());

        List full = populatedList(SIZE);
        assertFalse(full.isEmpty());
        assertTrue(full.subList(0, 0).isEmpty());
        assertTrue(full.subList(SIZE, SIZE).isEmpty());
    }

    /**
     * iterator() returns an iterator containing the elements of the
     * list in insertion order
     */
    public void testIterator() {
        Collection empty = new CopyOnWriteArrayList();
        assertFalse(empty.iterator().hasNext());
        try {
            empty.iterator().next();
            shouldThrow();
        } catch (NoSuchElementException success) {}

        Integer[] elements = new Integer[SIZE];
        for (int i = 0; i < SIZE; i++)
            elements[i] = i;
        shuffle(elements);
        Collection<Integer> full = populatedList(elements);

        Iterator it = full.iterator();
        for (int j = 0; j < SIZE; j++) {
            assertTrue(it.hasNext());
            assertEquals(elements[j], it.next());
        }
        assertIteratorExhausted(it);
    }

    /**
     * iterator of empty collection has no elements
     */
    public void testEmptyIterator() {
        Collection c = new CopyOnWriteArrayList();
        assertIteratorExhausted(c.iterator());
    }

    /**
     * iterator.remove throws UnsupportedOperationException
     */
    public void testIteratorRemove() {
        CopyOnWriteArrayList list = populatedList(SIZE);
        Iterator it = list.iterator();
        it.next();
        try {
            it.remove();
            shouldThrow();
        } catch (UnsupportedOperationException success) {}
    }

    /**
     * toString contains toString of elements
     */
    public void testToString() {
        assertEquals("[]", new CopyOnWriteArrayList().toString());
        List list = populatedList(3);
        String s = list.toString();
        for (int i = 0; i < 3; ++i)
            assertTrue(s.contains(String.valueOf(i)));
        assertEquals(new ArrayList(list).toString(),
                     list.toString());
    }

    /**
     * lastIndexOf(Object) returns the index of the last occurrence of
     * the specified element in this list, or -1 if this list does not
     * contain the element
     */
    public void testLastIndexOf1() {
        List list = populatedList(3);
        assertEquals(-1, list.lastIndexOf(-42));
        int size = list.size();
        for (int i = 0; i < size; i++) {
            assertEquals(i, list.lastIndexOf(i));
            assertEquals(i, list.subList(0, size).lastIndexOf(i));
            assertEquals(i, list.subList(0, i + 1).lastIndexOf(i));
            assertEquals(-1, list.subList(0, i).lastIndexOf(i));
            assertEquals(0, list.subList(i, size).lastIndexOf(i));
            assertEquals(-1, list.subList(i + 1, size).lastIndexOf(i));
        }

        list.add(1);
        assertEquals(size, list.lastIndexOf(1));
        assertEquals(size, list.subList(0, size + 1).lastIndexOf(1));
        assertEquals(1, list.subList(0, size).lastIndexOf(1));
        assertEquals(0, list.subList(1, 2).lastIndexOf(1));
        assertEquals(-1, list.subList(0, 1).indexOf(1));
    }

    /**
     * lastIndexOf(E, int) returns the index of the last occurrence of the
     * specified element in this list, searching backwards from index, or
     * returns -1 if the element is not found
     */
    public void testLastIndexOf2() {
        CopyOnWriteArrayList list = populatedList(3);

        // we might expect IOOBE, but spec says otherwise
        assertEquals(-1, list.lastIndexOf(0, -1));

        int size = list.size();
        assertThrows(
            IndexOutOfBoundsException.class,
            () -> list.lastIndexOf(0, size),
            () -> list.lastIndexOf(0, Integer.MAX_VALUE));

        for (int i = 0; i < size; i++) {
            assertEquals(i, list.lastIndexOf(i, i));
            assertEquals(list.indexOf(i), list.lastIndexOf(i, i));
            if (i > 0)
                assertEquals(-1, list.lastIndexOf(i, i - 1));
        }
        list.add(one);
        list.add(three);
        assertEquals(1, list.lastIndexOf(one, 1));
        assertEquals(1, list.lastIndexOf(one, 2));
        assertEquals(3, list.lastIndexOf(one, 3));
        assertEquals(3, list.lastIndexOf(one, 4));
        assertEquals(-1, list.lastIndexOf(three, 3));
    }

    /**
     * listIterator traverses all elements
     */
    public void testListIterator1() {
        List list = populatedList(SIZE);
        ListIterator i = list.listIterator();
        int j;
        for (j = 0; i.hasNext(); j++)
            assertEquals(j, i.next());
        assertEquals(SIZE, j);
    }

    /**
     * listIterator only returns those elements after the given index
     */
    public void testListIterator2() {
        List list = populatedList(3);
        ListIterator i = list.listIterator(1);
        int j;
        for (j = 0; i.hasNext(); j++)
            assertEquals(j + 1, i.next());
        assertEquals(2, j);
    }

    /**
     * remove(int) removes and returns the object at the given index
     */
    public void testRemove_int() {
        int SIZE = 3;
        for (int i = 0; i < SIZE; i++) {
            List list = populatedList(SIZE);
            assertEquals(i, list.remove(i));
            assertEquals(SIZE - 1, list.size());
            assertFalse(list.contains(new Integer(i)));
        }
    }

    /**
     * remove(Object) removes the object if found and returns true
     */
    public void testRemove_Object() {
        int SIZE = 3;
        for (int i = 0; i < SIZE; i++) {
            List list = populatedList(SIZE);
            assertFalse(list.remove(new Integer(-42)));
            assertTrue(list.remove(new Integer(i)));
            assertEquals(SIZE - 1, list.size());
            assertFalse(list.contains(new Integer(i)));
        }
        CopyOnWriteArrayList x = new CopyOnWriteArrayList(Arrays.asList(4, 5, 6));
        assertTrue(x.remove(new Integer(6)));
        assertEquals(x, Arrays.asList(4, 5));
        assertTrue(x.remove(new Integer(4)));
        assertEquals(x, Arrays.asList(5));
        assertTrue(x.remove(new Integer(5)));
        assertEquals(x, Arrays.asList());
        assertFalse(x.remove(new Integer(5)));
    }

    /**
     * removeAll removes all elements from the given collection
     */
    public void testRemoveAll() {
        List list = populatedList(3);
        assertTrue(list.removeAll(Arrays.asList(one, two)));
        assertEquals(1, list.size());
        assertFalse(list.removeAll(Arrays.asList(one, two)));
        assertEquals(1, list.size());
    }

    /**
     * set changes the element at the given index
     */
    public void testSet() {
        List list = populatedList(3);
        assertEquals(2, list.set(2, four));
        assertEquals(4, list.get(2));
    }

    /**
     * size returns the number of elements
     */
    public void testSize() {
        List empty = new CopyOnWriteArrayList();
        assertEquals(0, empty.size());
        assertEquals(0, empty.subList(0, 0).size());

        List full = populatedList(SIZE);
        assertEquals(SIZE, full.size());
        assertEquals(0, full.subList(0, 0).size());
        assertEquals(0, full.subList(SIZE, SIZE).size());
    }

    /**
     * toArray() returns an Object array containing all elements from
     * the list in insertion order
     */
    public void testToArray() {
        Object[] a = new CopyOnWriteArrayList().toArray();
        assertTrue(Arrays.equals(new Object[0], a));
        assertSame(Object[].class, a.getClass());

        Integer[] elements = new Integer[SIZE];
        for (int i = 0; i < SIZE; i++)
            elements[i] = i;
        shuffle(elements);
        Collection<Integer> full = populatedList(elements);

        assertTrue(Arrays.equals(elements, full.toArray()));
        assertSame(Object[].class, full.toArray().getClass());
    }

    /**
     * toArray(Integer array) returns an Integer array containing all
     * elements from the list in insertion order
     */
    public void testToArray2() {
        Collection empty = new CopyOnWriteArrayList();
        Integer[] a;

        a = new Integer[0];
        assertSame(a, empty.toArray(a));

        a = new Integer[SIZE / 2];
        Arrays.fill(a, 42);
        assertSame(a, empty.toArray(a));
        assertNull(a[0]);
        for (int i = 1; i < a.length; i++)
            assertEquals(42, (int) a[i]);

        Integer[] elements = new Integer[SIZE];
        for (int i = 0; i < SIZE; i++)
            elements[i] = i;
        shuffle(elements);
        Collection<Integer> full = populatedList(elements);

        Arrays.fill(a, 42);
        assertTrue(Arrays.equals(elements, full.toArray(a)));
        for (int i = 0; i < a.length; i++)
            assertEquals(42, (int) a[i]);
        assertSame(Integer[].class, full.toArray(a).getClass());

        a = new Integer[SIZE];
        Arrays.fill(a, 42);
        assertSame(a, full.toArray(a));
        assertTrue(Arrays.equals(elements, a));

        a = new Integer[2 * SIZE];
        Arrays.fill(a, 42);
        assertSame(a, full.toArray(a));
        assertTrue(Arrays.equals(elements, Arrays.copyOf(a, SIZE)));
        assertNull(a[SIZE]);
        for (int i = SIZE + 1; i < a.length; i++)
            assertEquals(42, (int) a[i]);
    }

    /**
     * sublists contains elements at indexes offset from their base
     */
    public void testSubList() {
        List a = populatedList(10);
        assertTrue(a.subList(1,1).isEmpty());
        for (int j = 0; j < 9; ++j) {
            for (int i = j ; i < 10; ++i) {
                List b = a.subList(j,i);
                for (int k = j; k < i; ++k) {
                    assertEquals(new Integer(k), b.get(k-j));
                }
            }
        }

        List s = a.subList(2, 5);
        assertEquals(3, s.size());
        s.set(2, m1);
        assertEquals(a.get(4), m1);
        s.clear();
        assertEquals(7, a.size());

        assertThrows(
            IndexOutOfBoundsException.class,
            () -> s.get(0),
            () -> s.set(0, 42));
    }

    // Exception tests

    /**
     * toArray throws an ArrayStoreException when the given array
     * can not store the objects inside the list
     */
    public void testToArray_ArrayStoreException() {
        List list = new CopyOnWriteArrayList();
        // Integers are not auto-converted to Longs
        list.add(86);
        list.add(99);
        assertThrows(
            ArrayStoreException.class,
            () -> list.toArray(new Long[0]),
            () -> list.toArray(new Long[5]));
    }

    void testIndexOutOfBoundsException(List list) {
        int size = list.size();
        assertThrows(
            IndexOutOfBoundsException.class,
            () -> list.get(-1),
            () -> list.get(size),
            () -> list.set(-1, "qwerty"),
            () -> list.set(size, "qwerty"),
            () -> list.add(-1, "qwerty"),
            () -> list.add(size + 1, "qwerty"),
            () -> list.remove(-1),
            () -> list.remove(size),
            () -> list.addAll(-1, Collections.emptyList()),
            () -> list.addAll(size + 1, Collections.emptyList()),
            () -> list.listIterator(-1),
            () -> list.listIterator(size + 1),
            () -> list.subList(-1, size),
            () -> list.subList(0, size + 1));

        // Conversely, operations that must not throw
        list.addAll(0, Collections.emptyList());
        list.addAll(size, Collections.emptyList());
        list.add(0, "qwerty");
        list.add(list.size(), "qwerty");
        list.get(0);
        list.get(list.size() - 1);
        list.set(0, "azerty");
        list.set(list.size() - 1, "azerty");
        list.listIterator(0);
        list.listIterator(list.size());
        list.subList(0, list.size());
        list.remove(list.size() - 1);
    }

    /**
     * IndexOutOfBoundsException is thrown when specified
     */
    public void testIndexOutOfBoundsException() {
        ThreadLocalRandom rnd = ThreadLocalRandom.current();
        List x = populatedList(rnd.nextInt(5));
        testIndexOutOfBoundsException(x);

        int start = rnd.nextInt(x.size() + 1);
        int end = rnd.nextInt(start, x.size() + 1);
        assertThrows(
            IndexOutOfBoundsException.class,
            () -> x.subList(start, start - 1));
        List subList = x.subList(start, end);
        testIndexOutOfBoundsException(x);
    }

    /**
     * a deserialized/reserialized list equals original
     */
    public void testSerialization() throws Exception {
        List x = populatedList(SIZE);
        List y = serialClone(x);

        assertNotSame(x, y);
        assertEquals(x.size(), y.size());
        assertEquals(x.toString(), y.toString());
        assertTrue(Arrays.equals(x.toArray(), y.toArray()));
        assertEquals(x, y);
        assertEquals(y, x);
        while (!x.isEmpty()) {
            assertFalse(y.isEmpty());
            assertEquals(x.remove(0), y.remove(0));
        }
        assertTrue(y.isEmpty());
    }

}
Revision:	1.49
Committed:	Tue Apr 3 05:49:43 2018 UTC (6 years, 1 month ago) by jsr166
Branch:	MAIN
Changes since 1.48:	+6 -1 lines
Log Message:	add more randomness to sublist testing
#	Content
1	/*
2	* Written by Doug Lea with assistance from members of JCP JSR-166
3	* Expert Group and released to the public domain, as explained at
4	* http://creativecommons.org/publicdomain/zero/1.0/
5	* Other contributors include Andrew Wright, Jeffrey Hayes,
6	* Pat Fisher, Mike Judd.
7	*/
8
9	import java.util.ArrayList;
10	import java.util.Arrays;
11	import java.util.Collection;
12	import java.util.Collections;
13	import java.util.Iterator;
14	import java.util.List;
15	import java.util.ListIterator;
16	import java.util.NoSuchElementException;
17	import java.util.concurrent.CopyOnWriteArrayList;
18	import java.util.concurrent.ThreadLocalRandom;
19
20	import junit.framework.Test;
21
22	public class CopyOnWriteArrayListTest extends JSR166TestCase {
23
24	public static void main(String[] args) {
25	main(suite(), args);
26	}
27
28	public static Test suite() {
29	class Implementation implements CollectionImplementation {
30	public Class<?> klazz() { return CopyOnWriteArrayList.class; }
31	public List emptyCollection() { return new CopyOnWriteArrayList(); }
32	public Object makeElement(int i) { return i; }
33	public boolean isConcurrent() { return true; }
34	public boolean permitsNulls() { return true; }
35	}
36	class SubListImplementation extends Implementation {
37	public List emptyCollection() {
38	List list = super.emptyCollection();
39	ThreadLocalRandom rnd = ThreadLocalRandom.current();
40	if (rnd.nextBoolean())
41	list.add(makeElement(rnd.nextInt()));
42	int i = rnd.nextInt(list.size() + 1);
43	return list.subList(i, i);
44	}
45	}
46	return newTestSuite(
47	CopyOnWriteArrayListTest.class,
48	CollectionTest.testSuite(new Implementation()),
49	CollectionTest.testSuite(new SubListImplementation()));
50	}
51
52	static CopyOnWriteArrayList<Integer> populatedList(int n) {
53	CopyOnWriteArrayList<Integer> list = new CopyOnWriteArrayList<>();
54	assertTrue(list.isEmpty());
55	for (int i = 0; i < n; i++)
56	list.add(i);
57	assertEquals(n <= 0, list.isEmpty());
58	assertEquals(n, list.size());
59	return list;
60	}
61
62	static CopyOnWriteArrayList<Integer> populatedList(Integer[] elements) {
63	CopyOnWriteArrayList<Integer> list = new CopyOnWriteArrayList<>();
64	assertTrue(list.isEmpty());
65	for (Integer element : elements)
66	list.add(element);
67	assertFalse(list.isEmpty());
68	assertEquals(elements.length, list.size());
69	return list;
70	}
71
72	/**
73	* a new list is empty
74	*/
75	public void testConstructor() {
76	List list = new CopyOnWriteArrayList();
77	assertTrue(list.isEmpty());
78	}
79
80	/**
81	* new list contains all elements of initializing array
82	*/
83	public void testConstructor2() {
84	Integer[] elts = new Integer[SIZE];
85	for (int i = 0; i < SIZE - 1; ++i)
86	elts[i] = i;
87	List list = new CopyOnWriteArrayList(elts);
88	for (int i = 0; i < SIZE; ++i)
89	assertEquals(elts[i], list.get(i));
90	}
91
92	/**
93	* new list contains all elements of initializing collection
94	*/
95	public void testConstructor3() {
96	Integer[] elts = new Integer[SIZE];
97	for (int i = 0; i < SIZE - 1; ++i)
98	elts[i] = i;
99	List list = new CopyOnWriteArrayList(Arrays.asList(elts));
100	for (int i = 0; i < SIZE; ++i)
101	assertEquals(elts[i], list.get(i));
102	}
103
104	/**
105	* addAll adds each element from the given collection, including duplicates
106	*/
107	public void testAddAll() {
108	List list = populatedList(3);
109	assertTrue(list.addAll(Arrays.asList(three, four, five)));
110	assertEquals(6, list.size());
111	assertTrue(list.addAll(Arrays.asList(three, four, five)));
112	assertEquals(9, list.size());
113	}
114
115	/**
116	* addAllAbsent adds each element from the given collection that did not
117	* already exist in the List
118	*/
119	public void testAddAllAbsent() {
120	CopyOnWriteArrayList list = populatedList(3);
121	// "one" is duplicate and will not be added
122	assertEquals(2, list.addAllAbsent(Arrays.asList(three, four, one)));
123	assertEquals(5, list.size());
124	assertEquals(0, list.addAllAbsent(Arrays.asList(three, four, one)));
125	assertEquals(5, list.size());
126	}
127
128	/**
129	* addIfAbsent will not add the element if it already exists in the list
130	*/
131	public void testAddIfAbsent() {
132	CopyOnWriteArrayList list = populatedList(SIZE);
133	list.addIfAbsent(one);
134	assertEquals(SIZE, list.size());
135	}
136
137	/**
138	* addIfAbsent adds the element when it does not exist in the list
139	*/
140	public void testAddIfAbsent2() {
141	CopyOnWriteArrayList list = populatedList(SIZE);
142	list.addIfAbsent(three);
143	assertTrue(list.contains(three));
144	}
145
146	/**
147	* clear removes all elements from the list
148	*/
149	public void testClear() {
150	List list = populatedList(SIZE);
151	list.clear();
152	assertEquals(0, list.size());
153	}
154
155	/**
156	* Cloned list is equal
157	*/
158	public void testClone() {
159	CopyOnWriteArrayList l1 = populatedList(SIZE);
160	CopyOnWriteArrayList l2 = (CopyOnWriteArrayList)(l1.clone());
161	assertEquals(l1, l2);
162	l1.clear();
163	assertFalse(l1.equals(l2));
164	}
165
166	/**
167	* contains is true for added elements
168	*/
169	public void testContains() {
170	List list = populatedList(3);
171	assertTrue(list.contains(one));
172	assertFalse(list.contains(five));
173	}
174
175	/**
176	* adding at an index places it in the indicated index
177	*/
178	public void testAddIndex() {
179	List list = populatedList(3);
180	list.add(0, m1);
181	assertEquals(4, list.size());
182	assertEquals(m1, list.get(0));
183	assertEquals(zero, list.get(1));
184
185	list.add(2, m2);
186	assertEquals(5, list.size());
187	assertEquals(m2, list.get(2));
188	assertEquals(two, list.get(4));
189	}
190
191	/**
192	* lists with same elements are equal and have same hashCode
193	*/
194	public void testEquals() {
195	List a = populatedList(3);
196	List b = populatedList(3);
197	assertTrue(a.equals(b));
198	assertTrue(b.equals(a));
199	assertTrue(a.containsAll(b));
200	assertTrue(b.containsAll(a));
201	assertEquals(a.hashCode(), b.hashCode());
202	a.add(m1);
203	assertFalse(a.equals(b));
204	assertFalse(b.equals(a));
205	assertTrue(a.containsAll(b));
206	assertFalse(b.containsAll(a));
207	b.add(m1);
208	assertTrue(a.equals(b));
209	assertTrue(b.equals(a));
210	assertTrue(a.containsAll(b));
211	assertTrue(b.containsAll(a));
212	assertEquals(a.hashCode(), b.hashCode());
213
214	assertFalse(a.equals(null));
215	}
216
217	/**
218	* containsAll returns true for collections with subset of elements
219	*/
220	public void testContainsAll() {
221	List list = populatedList(3);
222	assertTrue(list.containsAll(Arrays.asList()));
223	assertTrue(list.containsAll(Arrays.asList(one)));
224	assertTrue(list.containsAll(Arrays.asList(one, two)));
225	assertFalse(list.containsAll(Arrays.asList(one, two, six)));
226	assertFalse(list.containsAll(Arrays.asList(six)));
227
228	try {
229	list.containsAll(null);
230	shouldThrow();
231	} catch (NullPointerException success) {}
232	}
233
234	/**
235	* get returns the value at the given index
236	*/
237	public void testGet() {
238	List list = populatedList(3);
239	assertEquals(0, list.get(0));
240	}
241
242	/**
243	* indexOf(Object) returns the index of the first occurrence of the
244	* specified element in this list, or -1 if this list does not
245	* contain the element
246	*/
247	public void testIndexOf() {
248	List list = populatedList(3);
249	assertEquals(-1, list.indexOf(-42));
250	int size = list.size();
251	for (int i = 0; i < size; i++) {
252	assertEquals(i, list.indexOf(i));
253	assertEquals(i, list.subList(0, size).indexOf(i));
254	assertEquals(i, list.subList(0, i + 1).indexOf(i));
255	assertEquals(-1, list.subList(0, i).indexOf(i));
256	assertEquals(0, list.subList(i, size).indexOf(i));
257	assertEquals(-1, list.subList(i + 1, size).indexOf(i));
258	}
259
260	list.add(1);
261	assertEquals(1, list.indexOf(1));
262	assertEquals(1, list.subList(0, size + 1).indexOf(1));
263	assertEquals(0, list.subList(1, size + 1).indexOf(1));
264	assertEquals(size - 2, list.subList(2, size + 1).indexOf(1));
265	assertEquals(0, list.subList(size, size + 1).indexOf(1));
266	assertEquals(-1, list.subList(size + 1, size + 1).indexOf(1));
267	}
268
269	/**
270	* indexOf(E, int) returns the index of the first occurrence of the
271	* specified element in this list, searching forwards from index,
272	* or returns -1 if the element is not found
273	*/
274	public void testIndexOf2() {
275	CopyOnWriteArrayList list = populatedList(3);
276	int size = list.size();
277	assertEquals(-1, list.indexOf(-42, 0));
278
279	// we might expect IOOBE, but spec says otherwise
280	assertEquals(-1, list.indexOf(0, size));
281	assertEquals(-1, list.indexOf(0, Integer.MAX_VALUE));
282
283	assertThrows(
284	IndexOutOfBoundsException.class,
285	() -> list.indexOf(0, -1),
286	() -> list.indexOf(0, Integer.MIN_VALUE));
287
288	for (int i = 0; i < size; i++) {
289	assertEquals(i, list.indexOf(i, 0));
290	assertEquals(i, list.indexOf(i, i));
291	assertEquals(-1, list.indexOf(i, i + 1));
292	}
293
294	list.add(1);
295	assertEquals(1, list.indexOf(1, 0));
296	assertEquals(1, list.indexOf(1, 1));
297	assertEquals(size, list.indexOf(1, 2));
298	assertEquals(size, list.indexOf(1, size));
299	}
300
301	/**
302	* isEmpty returns true when empty, else false
303	*/
304	public void testIsEmpty() {
305	List empty = new CopyOnWriteArrayList();
306	assertTrue(empty.isEmpty());
307	assertTrue(empty.subList(0, 0).isEmpty());
308
309	List full = populatedList(SIZE);
310	assertFalse(full.isEmpty());
311	assertTrue(full.subList(0, 0).isEmpty());
312	assertTrue(full.subList(SIZE, SIZE).isEmpty());
313	}
314
315	/**
316	* iterator() returns an iterator containing the elements of the
317	* list in insertion order
318	*/
319	public void testIterator() {
320	Collection empty = new CopyOnWriteArrayList();
321	assertFalse(empty.iterator().hasNext());
322	try {
323	empty.iterator().next();
324	shouldThrow();
325	} catch (NoSuchElementException success) {}
326
327	Integer[] elements = new Integer[SIZE];
328	for (int i = 0; i < SIZE; i++)
329	elements[i] = i;
330	shuffle(elements);
331	Collection<Integer> full = populatedList(elements);
332
333	Iterator it = full.iterator();
334	for (int j = 0; j < SIZE; j++) {
335	assertTrue(it.hasNext());
336	assertEquals(elements[j], it.next());
337	}
338	assertIteratorExhausted(it);
339	}
340
341	/**
342	* iterator of empty collection has no elements
343	*/
344	public void testEmptyIterator() {
345	Collection c = new CopyOnWriteArrayList();
346	assertIteratorExhausted(c.iterator());
347	}
348
349	/**
350	* iterator.remove throws UnsupportedOperationException
351	*/
352	public void testIteratorRemove() {
353	CopyOnWriteArrayList list = populatedList(SIZE);
354	Iterator it = list.iterator();
355	it.next();
356	try {
357	it.remove();
358	shouldThrow();
359	} catch (UnsupportedOperationException success) {}
360	}
361
362	/**
363	* toString contains toString of elements
364	*/
365	public void testToString() {
366	assertEquals("[]", new CopyOnWriteArrayList().toString());
367	List list = populatedList(3);
368	String s = list.toString();
369	for (int i = 0; i < 3; ++i)
370	assertTrue(s.contains(String.valueOf(i)));
371	assertEquals(new ArrayList(list).toString(),
372	list.toString());
373	}
374
375	/**
376	* lastIndexOf(Object) returns the index of the last occurrence of
377	* the specified element in this list, or -1 if this list does not
378	* contain the element
379	*/
380	public void testLastIndexOf1() {
381	List list = populatedList(3);
382	assertEquals(-1, list.lastIndexOf(-42));
383	int size = list.size();
384	for (int i = 0; i < size; i++) {
385	assertEquals(i, list.lastIndexOf(i));
386	assertEquals(i, list.subList(0, size).lastIndexOf(i));
387	assertEquals(i, list.subList(0, i + 1).lastIndexOf(i));
388	assertEquals(-1, list.subList(0, i).lastIndexOf(i));
389	assertEquals(0, list.subList(i, size).lastIndexOf(i));
390	assertEquals(-1, list.subList(i + 1, size).lastIndexOf(i));
391	}
392
393	list.add(1);
394	assertEquals(size, list.lastIndexOf(1));
395	assertEquals(size, list.subList(0, size + 1).lastIndexOf(1));
396	assertEquals(1, list.subList(0, size).lastIndexOf(1));
397	assertEquals(0, list.subList(1, 2).lastIndexOf(1));
398	assertEquals(-1, list.subList(0, 1).indexOf(1));
399	}
400
401	/**
402	* lastIndexOf(E, int) returns the index of the last occurrence of the
403	* specified element in this list, searching backwards from index, or
404	* returns -1 if the element is not found
405	*/
406	public void testLastIndexOf2() {
407	CopyOnWriteArrayList list = populatedList(3);
408
409	// we might expect IOOBE, but spec says otherwise
410	assertEquals(-1, list.lastIndexOf(0, -1));
411
412	int size = list.size();
413	assertThrows(
414	IndexOutOfBoundsException.class,
415	() -> list.lastIndexOf(0, size),
416	() -> list.lastIndexOf(0, Integer.MAX_VALUE));
417
418	for (int i = 0; i < size; i++) {
419	assertEquals(i, list.lastIndexOf(i, i));
420	assertEquals(list.indexOf(i), list.lastIndexOf(i, i));
421	if (i > 0)
422	assertEquals(-1, list.lastIndexOf(i, i - 1));
423	}
424	list.add(one);
425	list.add(three);
426	assertEquals(1, list.lastIndexOf(one, 1));
427	assertEquals(1, list.lastIndexOf(one, 2));
428	assertEquals(3, list.lastIndexOf(one, 3));
429	assertEquals(3, list.lastIndexOf(one, 4));
430	assertEquals(-1, list.lastIndexOf(three, 3));
431	}
432
433	/**
434	* listIterator traverses all elements
435	*/
436	public void testListIterator1() {
437	List list = populatedList(SIZE);
438	ListIterator i = list.listIterator();
439	int j;
440	for (j = 0; i.hasNext(); j++)
441	assertEquals(j, i.next());
442	assertEquals(SIZE, j);
443	}
444
445	/**
446	* listIterator only returns those elements after the given index
447	*/
448	public void testListIterator2() {
449	List list = populatedList(3);
450	ListIterator i = list.listIterator(1);
451	int j;
452	for (j = 0; i.hasNext(); j++)
453	assertEquals(j + 1, i.next());
454	assertEquals(2, j);
455	}
456
457	/**
458	* remove(int) removes and returns the object at the given index
459	*/
460	public void testRemove_int() {
461	int SIZE = 3;
462	for (int i = 0; i < SIZE; i++) {
463	List list = populatedList(SIZE);
464	assertEquals(i, list.remove(i));
465	assertEquals(SIZE - 1, list.size());
466	assertFalse(list.contains(new Integer(i)));
467	}
468	}
469
470	/**
471	* remove(Object) removes the object if found and returns true
472	*/
473	public void testRemove_Object() {
474	int SIZE = 3;
475	for (int i = 0; i < SIZE; i++) {
476	List list = populatedList(SIZE);
477	assertFalse(list.remove(new Integer(-42)));
478	assertTrue(list.remove(new Integer(i)));
479	assertEquals(SIZE - 1, list.size());
480	assertFalse(list.contains(new Integer(i)));
481	}
482	CopyOnWriteArrayList x = new CopyOnWriteArrayList(Arrays.asList(4, 5, 6));
483	assertTrue(x.remove(new Integer(6)));
484	assertEquals(x, Arrays.asList(4, 5));
485	assertTrue(x.remove(new Integer(4)));
486	assertEquals(x, Arrays.asList(5));
487	assertTrue(x.remove(new Integer(5)));
488	assertEquals(x, Arrays.asList());
489	assertFalse(x.remove(new Integer(5)));
490	}
491
492	/**
493	* removeAll removes all elements from the given collection
494	*/
495	public void testRemoveAll() {
496	List list = populatedList(3);
497	assertTrue(list.removeAll(Arrays.asList(one, two)));
498	assertEquals(1, list.size());
499	assertFalse(list.removeAll(Arrays.asList(one, two)));
500	assertEquals(1, list.size());
501	}
502
503	/**
504	* set changes the element at the given index
505	*/
506	public void testSet() {
507	List list = populatedList(3);
508	assertEquals(2, list.set(2, four));
509	assertEquals(4, list.get(2));
510	}
511
512	/**
513	* size returns the number of elements
514	*/
515	public void testSize() {
516	List empty = new CopyOnWriteArrayList();
517	assertEquals(0, empty.size());
518	assertEquals(0, empty.subList(0, 0).size());
519
520	List full = populatedList(SIZE);
521	assertEquals(SIZE, full.size());
522	assertEquals(0, full.subList(0, 0).size());
523	assertEquals(0, full.subList(SIZE, SIZE).size());
524	}
525
526	/**
527	* toArray() returns an Object array containing all elements from
528	* the list in insertion order
529	*/
530	public void testToArray() {
531	Object[] a = new CopyOnWriteArrayList().toArray();
532	assertTrue(Arrays.equals(new Object[0], a));
533	assertSame(Object[].class, a.getClass());
534
535	Integer[] elements = new Integer[SIZE];
536	for (int i = 0; i < SIZE; i++)
537	elements[i] = i;
538	shuffle(elements);
539	Collection<Integer> full = populatedList(elements);
540
541	assertTrue(Arrays.equals(elements, full.toArray()));
542	assertSame(Object[].class, full.toArray().getClass());
543	}
544
545	/**
546	* toArray(Integer array) returns an Integer array containing all
547	* elements from the list in insertion order
548	*/
549	public void testToArray2() {
550	Collection empty = new CopyOnWriteArrayList();
551	Integer[] a;
552
553	a = new Integer[0];
554	assertSame(a, empty.toArray(a));
555
556	a = new Integer[SIZE / 2];
557	Arrays.fill(a, 42);
558	assertSame(a, empty.toArray(a));
559	assertNull(a[0]);
560	for (int i = 1; i < a.length; i++)
561	assertEquals(42, (int) a[i]);
562
563	Integer[] elements = new Integer[SIZE];
564	for (int i = 0; i < SIZE; i++)
565	elements[i] = i;
566	shuffle(elements);
567	Collection<Integer> full = populatedList(elements);
568
569	Arrays.fill(a, 42);
570	assertTrue(Arrays.equals(elements, full.toArray(a)));
571	for (int i = 0; i < a.length; i++)
572	assertEquals(42, (int) a[i]);
573	assertSame(Integer[].class, full.toArray(a).getClass());
574
575	a = new Integer[SIZE];
576	Arrays.fill(a, 42);
577	assertSame(a, full.toArray(a));
578	assertTrue(Arrays.equals(elements, a));
579
580	a = new Integer[2 * SIZE];
581	Arrays.fill(a, 42);
582	assertSame(a, full.toArray(a));
583	assertTrue(Arrays.equals(elements, Arrays.copyOf(a, SIZE)));
584	assertNull(a[SIZE]);
585	for (int i = SIZE + 1; i < a.length; i++)
586	assertEquals(42, (int) a[i]);
587	}
588
589	/**
590	* sublists contains elements at indexes offset from their base
591	*/
592	public void testSubList() {
593	List a = populatedList(10);
594	assertTrue(a.subList(1,1).isEmpty());
595	for (int j = 0; j < 9; ++j) {
596	for (int i = j ; i < 10; ++i) {
597	List b = a.subList(j,i);
598	for (int k = j; k < i; ++k) {
599	assertEquals(new Integer(k), b.get(k-j));
600	}
601	}
602	}
603
604	List s = a.subList(2, 5);
605	assertEquals(3, s.size());
606	s.set(2, m1);
607	assertEquals(a.get(4), m1);
608	s.clear();
609	assertEquals(7, a.size());
610
611	assertThrows(
612	IndexOutOfBoundsException.class,
613	() -> s.get(0),
614	() -> s.set(0, 42));
615	}
616
617	// Exception tests
618
619	/**
620	* toArray throws an ArrayStoreException when the given array
621	* can not store the objects inside the list
622	*/
623	public void testToArray_ArrayStoreException() {
624	List list = new CopyOnWriteArrayList();
625	// Integers are not auto-converted to Longs
626	list.add(86);
627	list.add(99);
628	assertThrows(
629	ArrayStoreException.class,
630	() -> list.toArray(new Long[0]),
631	() -> list.toArray(new Long[5]));
632	}
633
634	void testIndexOutOfBoundsException(List list) {
635	int size = list.size();
636	assertThrows(
637	IndexOutOfBoundsException.class,
638	() -> list.get(-1),
639	() -> list.get(size),
640	() -> list.set(-1, "qwerty"),
641	() -> list.set(size, "qwerty"),
642	() -> list.add(-1, "qwerty"),
643	() -> list.add(size + 1, "qwerty"),
644	() -> list.remove(-1),
645	() -> list.remove(size),
646	() -> list.addAll(-1, Collections.emptyList()),
647	() -> list.addAll(size + 1, Collections.emptyList()),
648	() -> list.listIterator(-1),
649	() -> list.listIterator(size + 1),
650	() -> list.subList(-1, size),
651	() -> list.subList(0, size + 1));
652
653	// Conversely, operations that must not throw
654	list.addAll(0, Collections.emptyList());
655	list.addAll(size, Collections.emptyList());
656	list.add(0, "qwerty");
657	list.add(list.size(), "qwerty");
658	list.get(0);
659	list.get(list.size() - 1);
660	list.set(0, "azerty");
661	list.set(list.size() - 1, "azerty");
662	list.listIterator(0);
663	list.listIterator(list.size());
664	list.subList(0, list.size());
665	list.remove(list.size() - 1);
666	}
667
668	/**
669	* IndexOutOfBoundsException is thrown when specified
670	*/
671	public void testIndexOutOfBoundsException() {
672	ThreadLocalRandom rnd = ThreadLocalRandom.current();
673	List x = populatedList(rnd.nextInt(5));
674	testIndexOutOfBoundsException(x);
675
676	int start = rnd.nextInt(x.size() + 1);
677	int end = rnd.nextInt(start, x.size() + 1);
678	assertThrows(
679	IndexOutOfBoundsException.class,
680	() -> x.subList(start, start - 1));
681	List subList = x.subList(start, end);
682	testIndexOutOfBoundsException(x);
683	}
684
685	/**
686	* a deserialized/reserialized list equals original
687	*/
688	public void testSerialization() throws Exception {
689	List x = populatedList(SIZE);
690	List y = serialClone(x);
691
692	assertNotSame(x, y);
693	assertEquals(x.size(), y.size());
694	assertEquals(x.toString(), y.toString());
695	assertTrue(Arrays.equals(x.toArray(), y.toArray()));
696	assertEquals(x, y);
697	assertEquals(y, x);
698	while (!x.isEmpty()) {
699	assertFalse(y.isEmpty());
700	assertEquals(x.remove(0), y.remove(0));
701	}
702	assertTrue(y.isEmpty());
703	}
704
705	}