test/tck/LinkedListTest.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.Arrays;
import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.NoSuchElementException;

import junit.framework.Test;
import junit.framework.TestSuite;

public class LinkedListTest extends JSR166TestCase {
    public static void main(String[] args) {
        main(suite(), args);
    }

    public static Test suite() {
        return new TestSuite(LinkedListTest.class);
    }

    /**
     * Returns a new queue of given size containing consecutive
     * Integers 0 ... n.
     */
    private LinkedList<Integer> populatedQueue(int n) {
        LinkedList<Integer> q = new LinkedList<Integer>();
        assertTrue(q.isEmpty());
        for (int i = 0; i < n; ++i)
            assertTrue(q.offer(new Integer(i)));
        assertFalse(q.isEmpty());
        assertEquals(n, q.size());
        return q;
    }

    /**
     * new queue is empty
     */
    public void testConstructor1() {
        assertEquals(0, new LinkedList().size());
    }

    /**
     * Initializing from null Collection throws NPE
     */
    public void testConstructor3() {
        try {
            new LinkedList((Collection)null);
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * Queue contains all elements of collection used to initialize
     */
    public void testConstructor6() {
        Integer[] ints = new Integer[SIZE];
        for (int i = 0; i < SIZE; ++i)
            ints[i] = i;
        LinkedList q = new LinkedList(Arrays.asList(ints));
        for (int i = 0; i < SIZE; ++i)
            assertEquals(ints[i], q.poll());
    }

    /**
     * isEmpty is true before add, false after
     */
    public void testEmpty() {
        LinkedList q = new LinkedList();
        assertTrue(q.isEmpty());
        q.add(new Integer(1));
        assertFalse(q.isEmpty());
        q.add(new Integer(2));
        q.remove();
        q.remove();
        assertTrue(q.isEmpty());
    }

    /**
     * size changes when elements added and removed
     */
    public void testSize() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(SIZE - i, q.size());
            q.remove();
        }
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.size());
            q.add(new Integer(i));
        }
    }

    /**
     * offer(null) succeeds
     */
    public void testOfferNull() {
        LinkedList q = new LinkedList();
        q.offer(null);
        assertNull(q.get(0));
        assertTrue(q.contains(null));
    }

    /**
     * Offer succeeds
     */
    public void testOffer() {
        LinkedList q = new LinkedList();
        assertTrue(q.offer(new Integer(0)));
        assertTrue(q.offer(new Integer(1)));
    }

    /**
     * add succeeds
     */
    public void testAdd() {
        LinkedList q = new LinkedList();
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.size());
            assertTrue(q.add(new Integer(i)));
        }
    }

    /**
     * addAll(null) throws NPE
     */
    public void testAddAll1() {
        LinkedList q = new LinkedList();
        try {
            q.addAll(null);
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * Queue contains all elements, in traversal order, of successful addAll
     */
    public void testAddAll5() {
        Integer[] empty = new Integer[0];
        Integer[] ints = new Integer[SIZE];
        for (int i = 0; i < SIZE; ++i)
            ints[i] = i;
        LinkedList q = new LinkedList();
        assertFalse(q.addAll(Arrays.asList(empty)));
        assertTrue(q.addAll(Arrays.asList(ints)));
        for (int i = 0; i < SIZE; ++i)
            assertEquals(ints[i], q.poll());
    }

    /**
     * addAll with too large an index throws IOOBE
     */
    public void testAddAll2_IndexOutOfBoundsException() {
        LinkedList l = new LinkedList();
        l.add(new Object());
        LinkedList m = new LinkedList();
        m.add(new Object());
        try {
            l.addAll(4,m);
            shouldThrow();
        } catch (IndexOutOfBoundsException success) {}
    }

    /**
     * addAll with negative index throws IOOBE
     */
    public void testAddAll4_BadIndex() {
        LinkedList l = new LinkedList();
        l.add(new Object());
        LinkedList m = new LinkedList();
        m.add(new Object());
        try {
            l.addAll(-1,m);
            shouldThrow();
        } catch (IndexOutOfBoundsException success) {}
    }

    /**
     * poll succeeds unless empty
     */
    public void testPoll() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.poll());
        }
        assertNull(q.poll());
    }

    /**
     * peek returns next element, or null if empty
     */
    public void testPeek() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.peek());
            assertEquals(i, q.poll());
            assertTrue(q.peek() == null ||
                       !q.peek().equals(i));
        }
        assertNull(q.peek());
    }

    /**
     * element returns next element, or throws NSEE if empty
     */
    public void testElement() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.element());
            assertEquals(i, q.poll());
        }
        try {
            q.element();
            shouldThrow();
        } catch (NoSuchElementException success) {}
    }

    /**
     * remove removes next element, or throws NSEE if empty
     */
    public void testRemove() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.remove());
        }
        try {
            q.remove();
            shouldThrow();
        } catch (NoSuchElementException success) {}
    }

    /**
     * remove(x) removes x and returns true if present
     */
    public void testRemoveElement() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = 1; i < SIZE; i += 2) {
            assertTrue(q.contains(i));
            assertTrue(q.remove((Integer)i));
            assertFalse(q.contains(i));
            assertTrue(q.contains(i-1));
        }
        for (int i = 0; i < SIZE; i += 2) {
            assertTrue(q.contains(i));
            assertTrue(q.remove((Integer)i));
            assertFalse(q.contains(i));
            assertFalse(q.remove((Integer)(i+1)));
            assertFalse(q.contains(i+1));
        }
        assertTrue(q.isEmpty());
    }

    /**
     * contains(x) reports true when elements added but not yet removed
     */
    public void testContains() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertTrue(q.contains(new Integer(i)));
            q.poll();
            assertFalse(q.contains(new Integer(i)));
        }
    }

    /**
     * clear removes all elements
     */
    public void testClear() {
        LinkedList q = populatedQueue(SIZE);
        q.clear();
        assertTrue(q.isEmpty());
        assertEquals(0, q.size());
        assertTrue(q.add(new Integer(1)));
        assertFalse(q.isEmpty());
        q.clear();
        assertTrue(q.isEmpty());
    }

    /**
     * containsAll(c) is true when c contains a subset of elements
     */
    public void testContainsAll() {
        LinkedList q = populatedQueue(SIZE);
        LinkedList p = new LinkedList();
        for (int i = 0; i < SIZE; ++i) {
            assertTrue(q.containsAll(p));
            assertFalse(p.containsAll(q));
            assertTrue(p.add(new Integer(i)));
        }
        assertTrue(p.containsAll(q));
    }

    /**
     * retainAll(c) retains only those elements of c and reports true if changed
     */
    public void testRetainAll() {
        LinkedList q = populatedQueue(SIZE);
        LinkedList p = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            boolean changed = q.retainAll(p);
            if (i == 0)
                assertFalse(changed);
            else
                assertTrue(changed);

            assertTrue(q.containsAll(p));
            assertEquals(SIZE - i, q.size());
            p.remove();
        }
    }

    /**
     * removeAll(c) removes only those elements of c and reports true if changed
     */
    public void testRemoveAll() {
        for (int i = 1; i < SIZE; ++i) {
            LinkedList q = populatedQueue(SIZE);
            LinkedList p = populatedQueue(i);
            assertTrue(q.removeAll(p));
            assertEquals(SIZE - i, q.size());
            for (int j = 0; j < i; ++j) {
                Integer x = (Integer)(p.remove());
                assertFalse(q.contains(x));
            }
        }
    }

    /**
     * toArray contains all elements in FIFO order
     */
    public void testToArray() {
        LinkedList q = populatedQueue(SIZE);
        Object[] o = q.toArray();
        for (int i = 0; i < o.length; i++)
            assertSame(o[i], q.poll());
    }

    /**
     * toArray(a) contains all elements in FIFO order
     */
    public void testToArray2() {
        LinkedList<Integer> q = populatedQueue(SIZE);
        Integer[] ints = new Integer[SIZE];
        Integer[] array = q.toArray(ints);
        assertSame(ints, array);
        for (int i = 0; i < ints.length; i++)
            assertSame(ints[i], q.poll());
    }

    /**
     * toArray(null) throws NullPointerException
     */
    public void testToArray_NullArg() {
        LinkedList l = new LinkedList();
        l.add(new Object());
        try {
            l.toArray(null);
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * toArray(incompatible array type) throws ArrayStoreException
     */
    public void testToArray1_BadArg() {
        LinkedList l = new LinkedList();
        l.add(new Integer(5));
        try {
            l.toArray(new String[10]);
            shouldThrow();
        } catch (ArrayStoreException success) {}
    }

    /**
     * iterator iterates through all elements
     */
    public void testIterator() {
        LinkedList q = populatedQueue(SIZE);
        Iterator it = q.iterator();
        int i;
        for (i = 0; it.hasNext(); i++)
            assertTrue(q.contains(it.next()));
        assertEquals(i, SIZE);
        assertIteratorExhausted(it);
    }

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

    /**
     * iterator ordering is FIFO
     */
    public void testIteratorOrdering() {
        final LinkedList q = new LinkedList();
        q.add(new Integer(1));
        q.add(new Integer(2));
        q.add(new Integer(3));
        int k = 0;
        for (Iterator it = q.iterator(); it.hasNext();) {
            assertEquals(++k, it.next());
        }

        assertEquals(3, k);
    }

    /**
     * iterator.remove removes current element
     */
    public void testIteratorRemove() {
        final LinkedList q = new LinkedList();
        q.add(new Integer(1));
        q.add(new Integer(2));
        q.add(new Integer(3));
        Iterator it = q.iterator();
        assertEquals(1, it.next());
        it.remove();
        it = q.iterator();
        assertEquals(2, it.next());
        assertEquals(3, it.next());
        assertFalse(it.hasNext());
    }

    /**
     * Descending iterator iterates through all elements
     */
    public void testDescendingIterator() {
        LinkedList q = populatedQueue(SIZE);
        int i = 0;
        Iterator it = q.descendingIterator();
        while (it.hasNext()) {
            assertTrue(q.contains(it.next()));
            ++i;
        }
        assertEquals(i, SIZE);
        assertFalse(it.hasNext());
        try {
            it.next();
            shouldThrow();
        } catch (NoSuchElementException success) {}
    }

    /**
     * Descending iterator ordering is reverse FIFO
     */
    public void testDescendingIteratorOrdering() {
        final LinkedList q = new LinkedList();
        q.add(new Integer(3));
        q.add(new Integer(2));
        q.add(new Integer(1));
        int k = 0;
        for (Iterator it = q.descendingIterator(); it.hasNext();) {
            assertEquals(++k, it.next());
        }

        assertEquals(3, k);
    }

    /**
     * descendingIterator.remove removes current element
     */
    public void testDescendingIteratorRemove() {
        final LinkedList q = new LinkedList();
        q.add(three);
        q.add(two);
        q.add(one);
        Iterator it = q.descendingIterator();
        it.next();
        it.remove();
        it = q.descendingIterator();
        assertSame(it.next(), two);
        assertSame(it.next(), three);
        assertFalse(it.hasNext());
    }

    /**
     * toString contains toStrings of elements
     */
    public void testToString() {
        LinkedList q = populatedQueue(SIZE);
        String s = q.toString();
        for (int i = 0; i < SIZE; ++i) {
            assertTrue(s.contains(String.valueOf(i)));
        }
    }

    /**
     * peek returns element inserted with addFirst
     */
    public void testAddFirst() {
        LinkedList q = populatedQueue(3);
        q.addFirst(four);
        assertSame(four, q.peek());
    }

    /**
     * peekFirst returns element inserted with push
     */
    public void testPush() {
        LinkedList q = populatedQueue(3);
        q.push(four);
        assertSame(four, q.peekFirst());
    }

    /**
     * pop removes next element, or throws NSEE if empty
     */
    public void testPop() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.pop());
        }
        try {
            q.pop();
            shouldThrow();
        } catch (NoSuchElementException success) {}
    }

    /**
     * OfferFirst succeeds
     */
    public void testOfferFirst() {
        LinkedList q = new LinkedList();
        assertTrue(q.offerFirst(new Integer(0)));
        assertTrue(q.offerFirst(new Integer(1)));
    }

    /**
     * OfferLast succeeds
     */
    public void testOfferLast() {
        LinkedList q = new LinkedList();
        assertTrue(q.offerLast(new Integer(0)));
        assertTrue(q.offerLast(new Integer(1)));
    }

    /**
     * pollLast succeeds unless empty
     */
    public void testPollLast() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = SIZE - 1; i >= 0; --i) {
            assertEquals(i, q.pollLast());
        }
        assertNull(q.pollLast());
    }

    /**
     * peekFirst returns next element, or null if empty
     */
    public void testPeekFirst() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.peekFirst());
            assertEquals(i, q.pollFirst());
            assertTrue(q.peekFirst() == null ||
                       !q.peekFirst().equals(i));
        }
        assertNull(q.peekFirst());
    }

    /**
     * peekLast returns next element, or null if empty
     */
    public void testPeekLast() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = SIZE - 1; i >= 0; --i) {
            assertEquals(i, q.peekLast());
            assertEquals(i, q.pollLast());
            assertTrue(q.peekLast() == null ||
                       !q.peekLast().equals(i));
        }
        assertNull(q.peekLast());
    }

    public void testFirstElement() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertEquals(i, q.getFirst());
            assertEquals(i, q.pollFirst());
        }
        try {
            q.getFirst();
            shouldThrow();
        } catch (NoSuchElementException success) {}
    }

    /**
     * getLast returns next element, or throws NSEE if empty
     */
    public void testLastElement() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = SIZE - 1; i >= 0; --i) {
            assertEquals(i, q.getLast());
            assertEquals(i, q.pollLast());
        }
        try {
            q.getLast();
            shouldThrow();
        } catch (NoSuchElementException success) {}
        assertNull(q.peekLast());
    }

    /**
     * removeFirstOccurrence(x) removes x and returns true if present
     */
    public void testRemoveFirstOccurrence() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = 1; i < SIZE; i += 2) {
            assertTrue(q.removeFirstOccurrence(new Integer(i)));
        }
        for (int i = 0; i < SIZE; i += 2) {
            assertTrue(q.removeFirstOccurrence(new Integer(i)));
            assertFalse(q.removeFirstOccurrence(new Integer(i+1)));
        }
        assertTrue(q.isEmpty());
    }

    /**
     * removeLastOccurrence(x) removes x and returns true if present
     */
    public void testRemoveLastOccurrence() {
        LinkedList q = populatedQueue(SIZE);
        for (int i = 1; i < SIZE; i += 2) {
            assertTrue(q.removeLastOccurrence(new Integer(i)));
        }
        for (int i = 0; i < SIZE; i += 2) {
            assertTrue(q.removeLastOccurrence(new Integer(i)));
            assertFalse(q.removeLastOccurrence(new Integer(i+1)));
        }
        assertTrue(q.isEmpty());
    }

}
Revision:	1.39
Committed:	Sat May 23 00:53:08 2015 UTC (8 years, 11 months ago) by jsr166
Branch:	MAIN
Changes since 1.38:	+6 -6 lines
Log Message:	whitespace
#	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.Arrays;
10	import java.util.Collection;
11	import java.util.Iterator;
12	import java.util.LinkedList;
13	import java.util.NoSuchElementException;
14
15	import junit.framework.Test;
16	import junit.framework.TestSuite;
17
18	public class LinkedListTest extends JSR166TestCase {
19	public static void main(String[] args) {
20	main(suite(), args);
21	}
22
23	public static Test suite() {
24	return new TestSuite(LinkedListTest.class);
25	}
26
27	/**
28	* Returns a new queue of given size containing consecutive
29	* Integers 0 ... n.
30	*/
31	private LinkedList<Integer> populatedQueue(int n) {
32	LinkedList<Integer> q = new LinkedList<Integer>();
33	assertTrue(q.isEmpty());
34	for (int i = 0; i < n; ++i)
35	assertTrue(q.offer(new Integer(i)));
36	assertFalse(q.isEmpty());
37	assertEquals(n, q.size());
38	return q;
39	}
40
41	/**
42	* new queue is empty
43	*/
44	public void testConstructor1() {
45	assertEquals(0, new LinkedList().size());
46	}
47
48	/**
49	* Initializing from null Collection throws NPE
50	*/
51	public void testConstructor3() {
52	try {
53	new LinkedList((Collection)null);
54	shouldThrow();
55	} catch (NullPointerException success) {}
56	}
57
58	/**
59	* Queue contains all elements of collection used to initialize
60	*/
61	public void testConstructor6() {
62	Integer[] ints = new Integer[SIZE];
63	for (int i = 0; i < SIZE; ++i)
64	ints[i] = i;
65	LinkedList q = new LinkedList(Arrays.asList(ints));
66	for (int i = 0; i < SIZE; ++i)
67	assertEquals(ints[i], q.poll());
68	}
69
70	/**
71	* isEmpty is true before add, false after
72	*/
73	public void testEmpty() {
74	LinkedList q = new LinkedList();
75	assertTrue(q.isEmpty());
76	q.add(new Integer(1));
77	assertFalse(q.isEmpty());
78	q.add(new Integer(2));
79	q.remove();
80	q.remove();
81	assertTrue(q.isEmpty());
82	}
83
84	/**
85	* size changes when elements added and removed
86	*/
87	public void testSize() {
88	LinkedList q = populatedQueue(SIZE);
89	for (int i = 0; i < SIZE; ++i) {
90	assertEquals(SIZE - i, q.size());
91	q.remove();
92	}
93	for (int i = 0; i < SIZE; ++i) {
94	assertEquals(i, q.size());
95	q.add(new Integer(i));
96	}
97	}
98
99	/**
100	* offer(null) succeeds
101	*/
102	public void testOfferNull() {
103	LinkedList q = new LinkedList();
104	q.offer(null);
105	assertNull(q.get(0));
106	assertTrue(q.contains(null));
107	}
108
109	/**
110	* Offer succeeds
111	*/
112	public void testOffer() {
113	LinkedList q = new LinkedList();
114	assertTrue(q.offer(new Integer(0)));
115	assertTrue(q.offer(new Integer(1)));
116	}
117
118	/**
119	* add succeeds
120	*/
121	public void testAdd() {
122	LinkedList q = new LinkedList();
123	for (int i = 0; i < SIZE; ++i) {
124	assertEquals(i, q.size());
125	assertTrue(q.add(new Integer(i)));
126	}
127	}
128
129	/**
130	* addAll(null) throws NPE
131	*/
132	public void testAddAll1() {
133	LinkedList q = new LinkedList();
134	try {
135	q.addAll(null);
136	shouldThrow();
137	} catch (NullPointerException success) {}
138	}
139
140	/**
141	* Queue contains all elements, in traversal order, of successful addAll
142	*/
143	public void testAddAll5() {
144	Integer[] empty = new Integer[0];
145	Integer[] ints = new Integer[SIZE];
146	for (int i = 0; i < SIZE; ++i)
147	ints[i] = i;
148	LinkedList q = new LinkedList();
149	assertFalse(q.addAll(Arrays.asList(empty)));
150	assertTrue(q.addAll(Arrays.asList(ints)));
151	for (int i = 0; i < SIZE; ++i)
152	assertEquals(ints[i], q.poll());
153	}
154
155	/**
156	* addAll with too large an index throws IOOBE
157	*/
158	public void testAddAll2_IndexOutOfBoundsException() {
159	LinkedList l = new LinkedList();
160	l.add(new Object());
161	LinkedList m = new LinkedList();
162	m.add(new Object());
163	try {
164	l.addAll(4,m);
165	shouldThrow();
166	} catch (IndexOutOfBoundsException success) {}
167	}
168
169	/**
170	* addAll with negative index throws IOOBE
171	*/
172	public void testAddAll4_BadIndex() {
173	LinkedList l = new LinkedList();
174	l.add(new Object());
175	LinkedList m = new LinkedList();
176	m.add(new Object());
177	try {
178	l.addAll(-1,m);
179	shouldThrow();
180	} catch (IndexOutOfBoundsException success) {}
181	}
182
183	/**
184	* poll succeeds unless empty
185	*/
186	public void testPoll() {
187	LinkedList q = populatedQueue(SIZE);
188	for (int i = 0; i < SIZE; ++i) {
189	assertEquals(i, q.poll());
190	}
191	assertNull(q.poll());
192	}
193
194	/**
195	* peek returns next element, or null if empty
196	*/
197	public void testPeek() {
198	LinkedList q = populatedQueue(SIZE);
199	for (int i = 0; i < SIZE; ++i) {
200	assertEquals(i, q.peek());
201	assertEquals(i, q.poll());
202	assertTrue(q.peek() == null \|\|
203	!q.peek().equals(i));
204	}
205	assertNull(q.peek());
206	}
207
208	/**
209	* element returns next element, or throws NSEE if empty
210	*/
211	public void testElement() {
212	LinkedList q = populatedQueue(SIZE);
213	for (int i = 0; i < SIZE; ++i) {
214	assertEquals(i, q.element());
215	assertEquals(i, q.poll());
216	}
217	try {
218	q.element();
219	shouldThrow();
220	} catch (NoSuchElementException success) {}
221	}
222
223	/**
224	* remove removes next element, or throws NSEE if empty
225	*/
226	public void testRemove() {
227	LinkedList q = populatedQueue(SIZE);
228	for (int i = 0; i < SIZE; ++i) {
229	assertEquals(i, q.remove());
230	}
231	try {
232	q.remove();
233	shouldThrow();
234	} catch (NoSuchElementException success) {}
235	}
236
237	/**
238	* remove(x) removes x and returns true if present
239	*/
240	public void testRemoveElement() {
241	LinkedList q = populatedQueue(SIZE);
242	for (int i = 1; i < SIZE; i += 2) {
243	assertTrue(q.contains(i));
244	assertTrue(q.remove((Integer)i));
245	assertFalse(q.contains(i));
246	assertTrue(q.contains(i-1));
247	}
248	for (int i = 0; i < SIZE; i += 2) {
249	assertTrue(q.contains(i));
250	assertTrue(q.remove((Integer)i));
251	assertFalse(q.contains(i));
252	assertFalse(q.remove((Integer)(i+1)));
253	assertFalse(q.contains(i+1));
254	}
255	assertTrue(q.isEmpty());
256	}
257
258	/**
259	* contains(x) reports true when elements added but not yet removed
260	*/
261	public void testContains() {
262	LinkedList q = populatedQueue(SIZE);
263	for (int i = 0; i < SIZE; ++i) {
264	assertTrue(q.contains(new Integer(i)));
265	q.poll();
266	assertFalse(q.contains(new Integer(i)));
267	}
268	}
269
270	/**
271	* clear removes all elements
272	*/
273	public void testClear() {
274	LinkedList q = populatedQueue(SIZE);
275	q.clear();
276	assertTrue(q.isEmpty());
277	assertEquals(0, q.size());
278	assertTrue(q.add(new Integer(1)));
279	assertFalse(q.isEmpty());
280	q.clear();
281	assertTrue(q.isEmpty());
282	}
283
284	/**
285	* containsAll(c) is true when c contains a subset of elements
286	*/
287	public void testContainsAll() {
288	LinkedList q = populatedQueue(SIZE);
289	LinkedList p = new LinkedList();
290	for (int i = 0; i < SIZE; ++i) {
291	assertTrue(q.containsAll(p));
292	assertFalse(p.containsAll(q));
293	assertTrue(p.add(new Integer(i)));
294	}
295	assertTrue(p.containsAll(q));
296	}
297
298	/**
299	* retainAll(c) retains only those elements of c and reports true if changed
300	*/
301	public void testRetainAll() {
302	LinkedList q = populatedQueue(SIZE);
303	LinkedList p = populatedQueue(SIZE);
304	for (int i = 0; i < SIZE; ++i) {
305	boolean changed = q.retainAll(p);
306	if (i == 0)
307	assertFalse(changed);
308	else
309	assertTrue(changed);
310
311	assertTrue(q.containsAll(p));
312	assertEquals(SIZE - i, q.size());
313	p.remove();
314	}
315	}
316
317	/**
318	* removeAll(c) removes only those elements of c and reports true if changed
319	*/
320	public void testRemoveAll() {
321	for (int i = 1; i < SIZE; ++i) {
322	LinkedList q = populatedQueue(SIZE);
323	LinkedList p = populatedQueue(i);
324	assertTrue(q.removeAll(p));
325	assertEquals(SIZE - i, q.size());
326	for (int j = 0; j < i; ++j) {
327	Integer x = (Integer)(p.remove());
328	assertFalse(q.contains(x));
329	}
330	}
331	}
332
333	/**
334	* toArray contains all elements in FIFO order
335	*/
336	public void testToArray() {
337	LinkedList q = populatedQueue(SIZE);
338	Object[] o = q.toArray();
339	for (int i = 0; i < o.length; i++)
340	assertSame(o[i], q.poll());
341	}
342
343	/**
344	* toArray(a) contains all elements in FIFO order
345	*/
346	public void testToArray2() {
347	LinkedList<Integer> q = populatedQueue(SIZE);
348	Integer[] ints = new Integer[SIZE];
349	Integer[] array = q.toArray(ints);
350	assertSame(ints, array);
351	for (int i = 0; i < ints.length; i++)
352	assertSame(ints[i], q.poll());
353	}
354
355	/**
356	* toArray(null) throws NullPointerException
357	*/
358	public void testToArray_NullArg() {
359	LinkedList l = new LinkedList();
360	l.add(new Object());
361	try {
362	l.toArray(null);
363	shouldThrow();
364	} catch (NullPointerException success) {}
365	}
366
367	/**
368	* toArray(incompatible array type) throws ArrayStoreException
369	*/
370	public void testToArray1_BadArg() {
371	LinkedList l = new LinkedList();
372	l.add(new Integer(5));
373	try {
374	l.toArray(new String[10]);
375	shouldThrow();
376	} catch (ArrayStoreException success) {}
377	}
378
379	/**
380	* iterator iterates through all elements
381	*/
382	public void testIterator() {
383	LinkedList q = populatedQueue(SIZE);
384	Iterator it = q.iterator();
385	int i;
386	for (i = 0; it.hasNext(); i++)
387	assertTrue(q.contains(it.next()));
388	assertEquals(i, SIZE);
389	assertIteratorExhausted(it);
390	}
391
392	/**
393	* iterator of empty collection has no elements
394	*/
395	public void testEmptyIterator() {
396	assertIteratorExhausted(new LinkedList().iterator());
397	}
398
399	/**
400	* iterator ordering is FIFO
401	*/
402	public void testIteratorOrdering() {
403	final LinkedList q = new LinkedList();
404	q.add(new Integer(1));
405	q.add(new Integer(2));
406	q.add(new Integer(3));
407	int k = 0;
408	for (Iterator it = q.iterator(); it.hasNext();) {
409	assertEquals(++k, it.next());
410	}
411
412	assertEquals(3, k);
413	}
414
415	/**
416	* iterator.remove removes current element
417	*/
418	public void testIteratorRemove() {
419	final LinkedList q = new LinkedList();
420	q.add(new Integer(1));
421	q.add(new Integer(2));
422	q.add(new Integer(3));
423	Iterator it = q.iterator();
424	assertEquals(1, it.next());
425	it.remove();
426	it = q.iterator();
427	assertEquals(2, it.next());
428	assertEquals(3, it.next());
429	assertFalse(it.hasNext());
430	}
431
432	/**
433	* Descending iterator iterates through all elements
434	*/
435	public void testDescendingIterator() {
436	LinkedList q = populatedQueue(SIZE);
437	int i = 0;
438	Iterator it = q.descendingIterator();
439	while (it.hasNext()) {
440	assertTrue(q.contains(it.next()));
441	++i;
442	}
443	assertEquals(i, SIZE);
444	assertFalse(it.hasNext());
445	try {
446	it.next();
447	shouldThrow();
448	} catch (NoSuchElementException success) {}
449	}
450
451	/**
452	* Descending iterator ordering is reverse FIFO
453	*/
454	public void testDescendingIteratorOrdering() {
455	final LinkedList q = new LinkedList();
456	q.add(new Integer(3));
457	q.add(new Integer(2));
458	q.add(new Integer(1));
459	int k = 0;
460	for (Iterator it = q.descendingIterator(); it.hasNext();) {
461	assertEquals(++k, it.next());
462	}
463
464	assertEquals(3, k);
465	}
466
467	/**
468	* descendingIterator.remove removes current element
469	*/
470	public void testDescendingIteratorRemove() {
471	final LinkedList q = new LinkedList();
472	q.add(three);
473	q.add(two);
474	q.add(one);
475	Iterator it = q.descendingIterator();
476	it.next();
477	it.remove();
478	it = q.descendingIterator();
479	assertSame(it.next(), two);
480	assertSame(it.next(), three);
481	assertFalse(it.hasNext());
482	}
483
484	/**
485	* toString contains toStrings of elements
486	*/
487	public void testToString() {
488	LinkedList q = populatedQueue(SIZE);
489	String s = q.toString();
490	for (int i = 0; i < SIZE; ++i) {
491	assertTrue(s.contains(String.valueOf(i)));
492	}
493	}
494
495	/**
496	* peek returns element inserted with addFirst
497	*/
498	public void testAddFirst() {
499	LinkedList q = populatedQueue(3);
500	q.addFirst(four);
501	assertSame(four, q.peek());
502	}
503
504	/**
505	* peekFirst returns element inserted with push
506	*/
507	public void testPush() {
508	LinkedList q = populatedQueue(3);
509	q.push(four);
510	assertSame(four, q.peekFirst());
511	}
512
513	/**
514	* pop removes next element, or throws NSEE if empty
515	*/
516	public void testPop() {
517	LinkedList q = populatedQueue(SIZE);
518	for (int i = 0; i < SIZE; ++i) {
519	assertEquals(i, q.pop());
520	}
521	try {
522	q.pop();
523	shouldThrow();
524	} catch (NoSuchElementException success) {}
525	}
526
527	/**
528	* OfferFirst succeeds
529	*/
530	public void testOfferFirst() {
531	LinkedList q = new LinkedList();
532	assertTrue(q.offerFirst(new Integer(0)));
533	assertTrue(q.offerFirst(new Integer(1)));
534	}
535
536	/**
537	* OfferLast succeeds
538	*/
539	public void testOfferLast() {
540	LinkedList q = new LinkedList();
541	assertTrue(q.offerLast(new Integer(0)));
542	assertTrue(q.offerLast(new Integer(1)));
543	}
544
545	/**
546	* pollLast succeeds unless empty
547	*/
548	public void testPollLast() {
549	LinkedList q = populatedQueue(SIZE);
550	for (int i = SIZE - 1; i >= 0; --i) {
551	assertEquals(i, q.pollLast());
552	}
553	assertNull(q.pollLast());
554	}
555
556	/**
557	* peekFirst returns next element, or null if empty
558	*/
559	public void testPeekFirst() {
560	LinkedList q = populatedQueue(SIZE);
561	for (int i = 0; i < SIZE; ++i) {
562	assertEquals(i, q.peekFirst());
563	assertEquals(i, q.pollFirst());
564	assertTrue(q.peekFirst() == null \|\|
565	!q.peekFirst().equals(i));
566	}
567	assertNull(q.peekFirst());
568	}
569
570	/**
571	* peekLast returns next element, or null if empty
572	*/
573	public void testPeekLast() {
574	LinkedList q = populatedQueue(SIZE);
575	for (int i = SIZE - 1; i >= 0; --i) {
576	assertEquals(i, q.peekLast());
577	assertEquals(i, q.pollLast());
578	assertTrue(q.peekLast() == null \|\|
579	!q.peekLast().equals(i));
580	}
581	assertNull(q.peekLast());
582	}
583
584	public void testFirstElement() {
585	LinkedList q = populatedQueue(SIZE);
586	for (int i = 0; i < SIZE; ++i) {
587	assertEquals(i, q.getFirst());
588	assertEquals(i, q.pollFirst());
589	}
590	try {
591	q.getFirst();
592	shouldThrow();
593	} catch (NoSuchElementException success) {}
594	}
595
596	/**
597	* getLast returns next element, or throws NSEE if empty
598	*/
599	public void testLastElement() {
600	LinkedList q = populatedQueue(SIZE);
601	for (int i = SIZE - 1; i >= 0; --i) {
602	assertEquals(i, q.getLast());
603	assertEquals(i, q.pollLast());
604	}
605	try {
606	q.getLast();
607	shouldThrow();
608	} catch (NoSuchElementException success) {}
609	assertNull(q.peekLast());
610	}
611
612	/**
613	* removeFirstOccurrence(x) removes x and returns true if present
614	*/
615	public void testRemoveFirstOccurrence() {
616	LinkedList q = populatedQueue(SIZE);
617	for (int i = 1; i < SIZE; i += 2) {
618	assertTrue(q.removeFirstOccurrence(new Integer(i)));
619	}
620	for (int i = 0; i < SIZE; i += 2) {
621	assertTrue(q.removeFirstOccurrence(new Integer(i)));
622	assertFalse(q.removeFirstOccurrence(new Integer(i+1)));
623	}
624	assertTrue(q.isEmpty());
625	}
626
627	/**
628	* removeLastOccurrence(x) removes x and returns true if present
629	*/
630	public void testRemoveLastOccurrence() {
631	LinkedList q = populatedQueue(SIZE);
632	for (int i = 1; i < SIZE; i += 2) {
633	assertTrue(q.removeLastOccurrence(new Integer(i)));
634	}
635	for (int i = 0; i < SIZE; i += 2) {
636	assertTrue(q.removeLastOccurrence(new Integer(i)));
637	assertFalse(q.removeLastOccurrence(new Integer(i+1)));
638	}
639	assertTrue(q.isEmpty());
640	}
641
642	}