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 - 1.
     */
    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());
        assertEquals((Integer) 0, q.peekFirst());
        assertEquals((Integer) (n - 1), q.peekLast());
        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:	1.41
Committed:	Sun Oct 16 20:44:18 2016 UTC (7 years, 7 months ago) by jsr166
Branch:	MAIN
Changes since 1.40:	+3 -1 lines
Log Message:	improve populatedFoo methods
#	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 - 1.
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	assertEquals((Integer) 0, q.peekFirst());
39	assertEquals((Integer) (n - 1), q.peekLast());
40	return q;
41	}
42
43	/**
44	* new queue is empty
45	*/
46	public void testConstructor1() {
47	assertEquals(0, new LinkedList().size());
48	}
49
50	/**
51	* Initializing from null Collection throws NPE
52	*/
53	public void testConstructor3() {
54	try {
55	new LinkedList((Collection)null);
56	shouldThrow();
57	} catch (NullPointerException success) {}
58	}
59
60	/**
61	* Queue contains all elements of collection used to initialize
62	*/
63	public void testConstructor6() {
64	Integer[] ints = new Integer[SIZE];
65	for (int i = 0; i < SIZE; ++i)
66	ints[i] = i;
67	LinkedList q = new LinkedList(Arrays.asList(ints));
68	for (int i = 0; i < SIZE; ++i)
69	assertEquals(ints[i], q.poll());
70	}
71
72	/**
73	* isEmpty is true before add, false after
74	*/
75	public void testEmpty() {
76	LinkedList q = new LinkedList();
77	assertTrue(q.isEmpty());
78	q.add(new Integer(1));
79	assertFalse(q.isEmpty());
80	q.add(new Integer(2));
81	q.remove();
82	q.remove();
83	assertTrue(q.isEmpty());
84	}
85
86	/**
87	* size changes when elements added and removed
88	*/
89	public void testSize() {
90	LinkedList q = populatedQueue(SIZE);
91	for (int i = 0; i < SIZE; ++i) {
92	assertEquals(SIZE - i, q.size());
93	q.remove();
94	}
95	for (int i = 0; i < SIZE; ++i) {
96	assertEquals(i, q.size());
97	q.add(new Integer(i));
98	}
99	}
100
101	/**
102	* offer(null) succeeds
103	*/
104	public void testOfferNull() {
105	LinkedList q = new LinkedList();
106	q.offer(null);
107	assertNull(q.get(0));
108	assertTrue(q.contains(null));
109	}
110
111	/**
112	* Offer succeeds
113	*/
114	public void testOffer() {
115	LinkedList q = new LinkedList();
116	assertTrue(q.offer(new Integer(0)));
117	assertTrue(q.offer(new Integer(1)));
118	}
119
120	/**
121	* add succeeds
122	*/
123	public void testAdd() {
124	LinkedList q = new LinkedList();
125	for (int i = 0; i < SIZE; ++i) {
126	assertEquals(i, q.size());
127	assertTrue(q.add(new Integer(i)));
128	}
129	}
130
131	/**
132	* addAll(null) throws NPE
133	*/
134	public void testAddAll1() {
135	LinkedList q = new LinkedList();
136	try {
137	q.addAll(null);
138	shouldThrow();
139	} catch (NullPointerException success) {}
140	}
141
142	/**
143	* Queue contains all elements, in traversal order, of successful addAll
144	*/
145	public void testAddAll5() {
146	Integer[] empty = new Integer[0];
147	Integer[] ints = new Integer[SIZE];
148	for (int i = 0; i < SIZE; ++i)
149	ints[i] = i;
150	LinkedList q = new LinkedList();
151	assertFalse(q.addAll(Arrays.asList(empty)));
152	assertTrue(q.addAll(Arrays.asList(ints)));
153	for (int i = 0; i < SIZE; ++i)
154	assertEquals(ints[i], q.poll());
155	}
156
157	/**
158	* addAll with too large an index throws IOOBE
159	*/
160	public void testAddAll2_IndexOutOfBoundsException() {
161	LinkedList l = new LinkedList();
162	l.add(new Object());
163	LinkedList m = new LinkedList();
164	m.add(new Object());
165	try {
166	l.addAll(4,m);
167	shouldThrow();
168	} catch (IndexOutOfBoundsException success) {}
169	}
170
171	/**
172	* addAll with negative index throws IOOBE
173	*/
174	public void testAddAll4_BadIndex() {
175	LinkedList l = new LinkedList();
176	l.add(new Object());
177	LinkedList m = new LinkedList();
178	m.add(new Object());
179	try {
180	l.addAll(-1,m);
181	shouldThrow();
182	} catch (IndexOutOfBoundsException success) {}
183	}
184
185	/**
186	* poll succeeds unless empty
187	*/
188	public void testPoll() {
189	LinkedList q = populatedQueue(SIZE);
190	for (int i = 0; i < SIZE; ++i) {
191	assertEquals(i, q.poll());
192	}
193	assertNull(q.poll());
194	}
195
196	/**
197	* peek returns next element, or null if empty
198	*/
199	public void testPeek() {
200	LinkedList q = populatedQueue(SIZE);
201	for (int i = 0; i < SIZE; ++i) {
202	assertEquals(i, q.peek());
203	assertEquals(i, q.poll());
204	assertTrue(q.peek() == null \|\|
205	!q.peek().equals(i));
206	}
207	assertNull(q.peek());
208	}
209
210	/**
211	* element returns next element, or throws NSEE if empty
212	*/
213	public void testElement() {
214	LinkedList q = populatedQueue(SIZE);
215	for (int i = 0; i < SIZE; ++i) {
216	assertEquals(i, q.element());
217	assertEquals(i, q.poll());
218	}
219	try {
220	q.element();
221	shouldThrow();
222	} catch (NoSuchElementException success) {}
223	}
224
225	/**
226	* remove removes next element, or throws NSEE if empty
227	*/
228	public void testRemove() {
229	LinkedList q = populatedQueue(SIZE);
230	for (int i = 0; i < SIZE; ++i) {
231	assertEquals(i, q.remove());
232	}
233	try {
234	q.remove();
235	shouldThrow();
236	} catch (NoSuchElementException success) {}
237	}
238
239	/**
240	* remove(x) removes x and returns true if present
241	*/
242	public void testRemoveElement() {
243	LinkedList q = populatedQueue(SIZE);
244	for (int i = 1; i < SIZE; i += 2) {
245	assertTrue(q.contains(i));
246	assertTrue(q.remove((Integer)i));
247	assertFalse(q.contains(i));
248	assertTrue(q.contains(i - 1));
249	}
250	for (int i = 0; i < SIZE; i += 2) {
251	assertTrue(q.contains(i));
252	assertTrue(q.remove((Integer)i));
253	assertFalse(q.contains(i));
254	assertFalse(q.remove((Integer)(i + 1)));
255	assertFalse(q.contains(i + 1));
256	}
257	assertTrue(q.isEmpty());
258	}
259
260	/**
261	* contains(x) reports true when elements added but not yet removed
262	*/
263	public void testContains() {
264	LinkedList q = populatedQueue(SIZE);
265	for (int i = 0; i < SIZE; ++i) {
266	assertTrue(q.contains(new Integer(i)));
267	q.poll();
268	assertFalse(q.contains(new Integer(i)));
269	}
270	}
271
272	/**
273	* clear removes all elements
274	*/
275	public void testClear() {
276	LinkedList q = populatedQueue(SIZE);
277	q.clear();
278	assertTrue(q.isEmpty());
279	assertEquals(0, q.size());
280	assertTrue(q.add(new Integer(1)));
281	assertFalse(q.isEmpty());
282	q.clear();
283	assertTrue(q.isEmpty());
284	}
285
286	/**
287	* containsAll(c) is true when c contains a subset of elements
288	*/
289	public void testContainsAll() {
290	LinkedList q = populatedQueue(SIZE);
291	LinkedList p = new LinkedList();
292	for (int i = 0; i < SIZE; ++i) {
293	assertTrue(q.containsAll(p));
294	assertFalse(p.containsAll(q));
295	assertTrue(p.add(new Integer(i)));
296	}
297	assertTrue(p.containsAll(q));
298	}
299
300	/**
301	* retainAll(c) retains only those elements of c and reports true if changed
302	*/
303	public void testRetainAll() {
304	LinkedList q = populatedQueue(SIZE);
305	LinkedList p = populatedQueue(SIZE);
306	for (int i = 0; i < SIZE; ++i) {
307	boolean changed = q.retainAll(p);
308	if (i == 0)
309	assertFalse(changed);
310	else
311	assertTrue(changed);
312
313	assertTrue(q.containsAll(p));
314	assertEquals(SIZE - i, q.size());
315	p.remove();
316	}
317	}
318
319	/**
320	* removeAll(c) removes only those elements of c and reports true if changed
321	*/
322	public void testRemoveAll() {
323	for (int i = 1; i < SIZE; ++i) {
324	LinkedList q = populatedQueue(SIZE);
325	LinkedList p = populatedQueue(i);
326	assertTrue(q.removeAll(p));
327	assertEquals(SIZE - i, q.size());
328	for (int j = 0; j < i; ++j) {
329	Integer x = (Integer)(p.remove());
330	assertFalse(q.contains(x));
331	}
332	}
333	}
334
335	/**
336	* toArray contains all elements in FIFO order
337	*/
338	public void testToArray() {
339	LinkedList q = populatedQueue(SIZE);
340	Object[] o = q.toArray();
341	for (int i = 0; i < o.length; i++)
342	assertSame(o[i], q.poll());
343	}
344
345	/**
346	* toArray(a) contains all elements in FIFO order
347	*/
348	public void testToArray2() {
349	LinkedList<Integer> q = populatedQueue(SIZE);
350	Integer[] ints = new Integer[SIZE];
351	Integer[] array = q.toArray(ints);
352	assertSame(ints, array);
353	for (int i = 0; i < ints.length; i++)
354	assertSame(ints[i], q.poll());
355	}
356
357	/**
358	* toArray(null) throws NullPointerException
359	*/
360	public void testToArray_NullArg() {
361	LinkedList l = new LinkedList();
362	l.add(new Object());
363	try {
364	l.toArray(null);
365	shouldThrow();
366	} catch (NullPointerException success) {}
367	}
368
369	/**
370	* toArray(incompatible array type) throws ArrayStoreException
371	*/
372	public void testToArray1_BadArg() {
373	LinkedList l = new LinkedList();
374	l.add(new Integer(5));
375	try {
376	l.toArray(new String[10]);
377	shouldThrow();
378	} catch (ArrayStoreException success) {}
379	}
380
381	/**
382	* iterator iterates through all elements
383	*/
384	public void testIterator() {
385	LinkedList q = populatedQueue(SIZE);
386	Iterator it = q.iterator();
387	int i;
388	for (i = 0; it.hasNext(); i++)
389	assertTrue(q.contains(it.next()));
390	assertEquals(i, SIZE);
391	assertIteratorExhausted(it);
392	}
393
394	/**
395	* iterator of empty collection has no elements
396	*/
397	public void testEmptyIterator() {
398	assertIteratorExhausted(new LinkedList().iterator());
399	}
400
401	/**
402	* iterator ordering is FIFO
403	*/
404	public void testIteratorOrdering() {
405	final LinkedList q = new LinkedList();
406	q.add(new Integer(1));
407	q.add(new Integer(2));
408	q.add(new Integer(3));
409	int k = 0;
410	for (Iterator it = q.iterator(); it.hasNext();) {
411	assertEquals(++k, it.next());
412	}
413
414	assertEquals(3, k);
415	}
416
417	/**
418	* iterator.remove removes current element
419	*/
420	public void testIteratorRemove() {
421	final LinkedList q = new LinkedList();
422	q.add(new Integer(1));
423	q.add(new Integer(2));
424	q.add(new Integer(3));
425	Iterator it = q.iterator();
426	assertEquals(1, it.next());
427	it.remove();
428	it = q.iterator();
429	assertEquals(2, it.next());
430	assertEquals(3, it.next());
431	assertFalse(it.hasNext());
432	}
433
434	/**
435	* Descending iterator iterates through all elements
436	*/
437	public void testDescendingIterator() {
438	LinkedList q = populatedQueue(SIZE);
439	int i = 0;
440	Iterator it = q.descendingIterator();
441	while (it.hasNext()) {
442	assertTrue(q.contains(it.next()));
443	++i;
444	}
445	assertEquals(i, SIZE);
446	assertFalse(it.hasNext());
447	try {
448	it.next();
449	shouldThrow();
450	} catch (NoSuchElementException success) {}
451	}
452
453	/**
454	* Descending iterator ordering is reverse FIFO
455	*/
456	public void testDescendingIteratorOrdering() {
457	final LinkedList q = new LinkedList();
458	q.add(new Integer(3));
459	q.add(new Integer(2));
460	q.add(new Integer(1));
461	int k = 0;
462	for (Iterator it = q.descendingIterator(); it.hasNext();) {
463	assertEquals(++k, it.next());
464	}
465
466	assertEquals(3, k);
467	}
468
469	/**
470	* descendingIterator.remove removes current element
471	*/
472	public void testDescendingIteratorRemove() {
473	final LinkedList q = new LinkedList();
474	q.add(three);
475	q.add(two);
476	q.add(one);
477	Iterator it = q.descendingIterator();
478	it.next();
479	it.remove();
480	it = q.descendingIterator();
481	assertSame(it.next(), two);
482	assertSame(it.next(), three);
483	assertFalse(it.hasNext());
484	}
485
486	/**
487	* toString contains toStrings of elements
488	*/
489	public void testToString() {
490	LinkedList q = populatedQueue(SIZE);
491	String s = q.toString();
492	for (int i = 0; i < SIZE; ++i) {
493	assertTrue(s.contains(String.valueOf(i)));
494	}
495	}
496
497	/**
498	* peek returns element inserted with addFirst
499	*/
500	public void testAddFirst() {
501	LinkedList q = populatedQueue(3);
502	q.addFirst(four);
503	assertSame(four, q.peek());
504	}
505
506	/**
507	* peekFirst returns element inserted with push
508	*/
509	public void testPush() {
510	LinkedList q = populatedQueue(3);
511	q.push(four);
512	assertSame(four, q.peekFirst());
513	}
514
515	/**
516	* pop removes next element, or throws NSEE if empty
517	*/
518	public void testPop() {
519	LinkedList q = populatedQueue(SIZE);
520	for (int i = 0; i < SIZE; ++i) {
521	assertEquals(i, q.pop());
522	}
523	try {
524	q.pop();
525	shouldThrow();
526	} catch (NoSuchElementException success) {}
527	}
528
529	/**
530	* OfferFirst succeeds
531	*/
532	public void testOfferFirst() {
533	LinkedList q = new LinkedList();
534	assertTrue(q.offerFirst(new Integer(0)));
535	assertTrue(q.offerFirst(new Integer(1)));
536	}
537
538	/**
539	* OfferLast succeeds
540	*/
541	public void testOfferLast() {
542	LinkedList q = new LinkedList();
543	assertTrue(q.offerLast(new Integer(0)));
544	assertTrue(q.offerLast(new Integer(1)));
545	}
546
547	/**
548	* pollLast succeeds unless empty
549	*/
550	public void testPollLast() {
551	LinkedList q = populatedQueue(SIZE);
552	for (int i = SIZE - 1; i >= 0; --i) {
553	assertEquals(i, q.pollLast());
554	}
555	assertNull(q.pollLast());
556	}
557
558	/**
559	* peekFirst returns next element, or null if empty
560	*/
561	public void testPeekFirst() {
562	LinkedList q = populatedQueue(SIZE);
563	for (int i = 0; i < SIZE; ++i) {
564	assertEquals(i, q.peekFirst());
565	assertEquals(i, q.pollFirst());
566	assertTrue(q.peekFirst() == null \|\|
567	!q.peekFirst().equals(i));
568	}
569	assertNull(q.peekFirst());
570	}
571
572	/**
573	* peekLast returns next element, or null if empty
574	*/
575	public void testPeekLast() {
576	LinkedList q = populatedQueue(SIZE);
577	for (int i = SIZE - 1; i >= 0; --i) {
578	assertEquals(i, q.peekLast());
579	assertEquals(i, q.pollLast());
580	assertTrue(q.peekLast() == null \|\|
581	!q.peekLast().equals(i));
582	}
583	assertNull(q.peekLast());
584	}
585
586	public void testFirstElement() {
587	LinkedList q = populatedQueue(SIZE);
588	for (int i = 0; i < SIZE; ++i) {
589	assertEquals(i, q.getFirst());
590	assertEquals(i, q.pollFirst());
591	}
592	try {
593	q.getFirst();
594	shouldThrow();
595	} catch (NoSuchElementException success) {}
596	}
597
598	/**
599	* getLast returns next element, or throws NSEE if empty
600	*/
601	public void testLastElement() {
602	LinkedList q = populatedQueue(SIZE);
603	for (int i = SIZE - 1; i >= 0; --i) {
604	assertEquals(i, q.getLast());
605	assertEquals(i, q.pollLast());
606	}
607	try {
608	q.getLast();
609	shouldThrow();
610	} catch (NoSuchElementException success) {}
611	assertNull(q.peekLast());
612	}
613
614	/**
615	* removeFirstOccurrence(x) removes x and returns true if present
616	*/
617	public void testRemoveFirstOccurrence() {
618	LinkedList q = populatedQueue(SIZE);
619	for (int i = 1; i < SIZE; i += 2) {
620	assertTrue(q.removeFirstOccurrence(new Integer(i)));
621	}
622	for (int i = 0; i < SIZE; i += 2) {
623	assertTrue(q.removeFirstOccurrence(new Integer(i)));
624	assertFalse(q.removeFirstOccurrence(new Integer(i + 1)));
625	}
626	assertTrue(q.isEmpty());
627	}
628
629	/**
630	* removeLastOccurrence(x) removes x and returns true if present
631	*/
632	public void testRemoveLastOccurrence() {
633	LinkedList q = populatedQueue(SIZE);
634	for (int i = 1; i < SIZE; i += 2) {
635	assertTrue(q.removeLastOccurrence(new Integer(i)));
636	}
637	for (int i = 0; i < SIZE; i += 2) {
638	assertTrue(q.removeLastOccurrence(new Integer(i)));
639	assertFalse(q.removeLastOccurrence(new Integer(i + 1)));
640	}
641	assertTrue(q.isEmpty());
642	}
643
644	}