test/tck/PriorityQueueTest.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.Comparator;
import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.PriorityQueue;
import java.util.Queue;

import junit.framework.Test;

public class PriorityQueueTest extends JSR166TestCase {
    public static void main(String[] args) {
        main(suite(), args);
    }
    public static Test suite() {
        class Implementation implements CollectionImplementation {
            public Class<?> klazz() { return PriorityQueue.class; }
            public Collection emptyCollection() { return new PriorityQueue(); }
            public Object makeElement(int i) { return i; }
            public boolean isConcurrent() { return false; }
            public boolean permitsNulls() { return false; }
        }
        return newTestSuite(PriorityQueueTest.class,
                            CollectionTest.testSuite(new Implementation()));
    }

    static class MyReverseComparator implements Comparator {
        public int compare(Object x, Object y) {
            return ((Comparable)y).compareTo(x);
        }
    }

    /**
     * Returns a new queue of given size containing consecutive
     * Integers 0 ... n - 1.
     */
    private static PriorityQueue<Integer> populatedQueue(int n) {
        PriorityQueue<Integer> q = new PriorityQueue<>(n);
        assertTrue(q.isEmpty());
        for (int i = n - 1; i >= 0; i -= 2)
            assertTrue(q.offer(new Integer(i)));
        for (int i = (n & 1); i < n; i += 2)
            assertTrue(q.offer(new Integer(i)));
        assertFalse(q.isEmpty());
        assertEquals(n, q.size());
        assertEquals((Integer) 0, q.peek());
        return q;
    }

    /**
     * A new queue has unbounded capacity
     */
    public void testConstructor1() {
        assertEquals(0, new PriorityQueue(SIZE).size());
    }

    /**
     * Constructor throws IAE if capacity argument nonpositive
     */
    public void testConstructor2() {
        try {
            new PriorityQueue(0);
            shouldThrow();
        } catch (IllegalArgumentException success) {}
    }

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

    /**
     * Initializing from Collection of null elements throws NPE
     */
    public void testConstructor4() {
        try {
            new PriorityQueue(Arrays.asList(new Integer[SIZE]));
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * Initializing from Collection with some null elements throws NPE
     */
    public void testConstructor5() {
        Integer[] ints = new Integer[SIZE];
        for (int i = 0; i < SIZE - 1; ++i)
            ints[i] = new Integer(i);
        try {
            new PriorityQueue(Arrays.asList(ints));
            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] = new Integer(i);
        PriorityQueue q = new PriorityQueue(Arrays.asList(ints));
        for (int i = 0; i < SIZE; ++i)
            assertEquals(ints[i], q.poll());
    }

    /**
     * The comparator used in constructor is used
     */
    public void testConstructor7() {
        MyReverseComparator cmp = new MyReverseComparator();
        PriorityQueue q = new PriorityQueue(SIZE, cmp);
        assertEquals(cmp, q.comparator());
        Integer[] ints = new Integer[SIZE];
        for (int i = 0; i < SIZE; ++i)
            ints[i] = new Integer(i);
        q.addAll(Arrays.asList(ints));
        for (int i = SIZE - 1; i >= 0; --i)
            assertEquals(ints[i], q.poll());
    }

    /**
     * isEmpty is true before add, false after
     */
    public void testEmpty() {
        PriorityQueue q = new PriorityQueue(2);
        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() {
        PriorityQueue 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) throws NPE
     */
    public void testOfferNull() {
        PriorityQueue q = new PriorityQueue(1);
        try {
            q.offer(null);
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * add(null) throws NPE
     */
    public void testAddNull() {
        PriorityQueue q = new PriorityQueue(1);
        try {
            q.add(null);
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * Offer of comparable element succeeds
     */
    public void testOffer() {
        PriorityQueue q = new PriorityQueue(1);
        assertTrue(q.offer(zero));
        assertTrue(q.offer(one));
    }

    /**
     * Offer of non-Comparable throws CCE
     */
    public void testOfferNonComparable() {
        PriorityQueue q = new PriorityQueue(1);
        try {
            q.offer(new Object());
            shouldThrow();
        } catch (ClassCastException success) {
            assertTrue(q.isEmpty());
            assertEquals(0, q.size());
            assertNull(q.poll());
        }
    }

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

    /**
     * addAll(null) throws NPE
     */
    public void testAddAll1() {
        PriorityQueue q = new PriorityQueue(1);
        try {
            q.addAll(null);
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * addAll of a collection with null elements throws NPE
     */
    public void testAddAll2() {
        PriorityQueue q = new PriorityQueue(SIZE);
        try {
            q.addAll(Arrays.asList(new Integer[SIZE]));
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * addAll of a collection with any null elements throws NPE after
     * possibly adding some elements
     */
    public void testAddAll3() {
        PriorityQueue q = new PriorityQueue(SIZE);
        Integer[] ints = new Integer[SIZE];
        for (int i = 0; i < SIZE - 1; ++i)
            ints[i] = new Integer(i);
        try {
            q.addAll(Arrays.asList(ints));
            shouldThrow();
        } catch (NullPointerException success) {}
    }

    /**
     * Queue contains all elements 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] = new Integer(SIZE - 1 - i);
        PriorityQueue q = new PriorityQueue(SIZE);
        assertFalse(q.addAll(Arrays.asList(empty)));
        assertTrue(q.addAll(Arrays.asList(ints)));
        for (int i = 0; i < SIZE; ++i)
            assertEquals(new Integer(i), q.poll());
    }

    /**
     * poll succeeds unless empty
     */
    public void testPoll() {
        PriorityQueue 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() {
        PriorityQueue 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() {
        PriorityQueue 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() {
        PriorityQueue 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() {
        PriorityQueue q = populatedQueue(SIZE);
        for (int i = 1; i < SIZE; i += 2) {
            assertTrue(q.contains(i));
            assertTrue(q.remove(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(i));
            assertFalse(q.contains(i));
            assertFalse(q.remove(i + 1));
            assertFalse(q.contains(i + 1));
        }
        assertTrue(q.isEmpty());
    }

    /**
     * contains(x) reports true when elements added but not yet removed
     */
    public void testContains() {
        PriorityQueue 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() {
        PriorityQueue q = populatedQueue(SIZE);
        q.clear();
        assertTrue(q.isEmpty());
        assertEquals(0, q.size());
        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() {
        PriorityQueue q = populatedQueue(SIZE);
        PriorityQueue p = new PriorityQueue(SIZE);
        for (int i = 0; i < SIZE; ++i) {
            assertTrue(q.containsAll(p));
            assertFalse(p.containsAll(q));
            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() {
        PriorityQueue q = populatedQueue(SIZE);
        PriorityQueue 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) {
            PriorityQueue q = populatedQueue(SIZE);
            PriorityQueue 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
     */
    public void testToArray() {
        PriorityQueue q = populatedQueue(SIZE);
        Object[] o = q.toArray();
        Arrays.sort(o);
        for (int i = 0; i < o.length; i++)
            assertSame(o[i], q.poll());
    }

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

    /**
     * iterator iterates through all elements
     */
    public void testIterator() {
        PriorityQueue 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 PriorityQueue().iterator());
    }

    /**
     * iterator.remove removes current element
     */
    public void testIteratorRemove() {
        final PriorityQueue q = new PriorityQueue(3);
        q.add(new Integer(2));
        q.add(new Integer(1));
        q.add(new Integer(3));

        Iterator it = q.iterator();
        it.next();
        it.remove();

        it = q.iterator();
        assertEquals(it.next(), new Integer(2));
        assertEquals(it.next(), new Integer(3));
        assertFalse(it.hasNext());
    }

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

    /**
     * A deserialized serialized queue has same elements
     */
    public void testSerialization() throws Exception {
        Queue x = populatedQueue(SIZE);
        Queue y = serialClone(x);

        assertNotSame(x, y);
        assertEquals(x.size(), y.size());
        while (!x.isEmpty()) {
            assertFalse(y.isEmpty());
            assertEquals(x.remove(), y.remove());
        }
        assertTrue(y.isEmpty());
    }
}
Revision:	1.42
Committed:	Sat Mar 11 18:20:47 2017 UTC (7 years, 1 month ago) by jsr166
Branch:	MAIN
Changes since 1.41:	+1 -1 lines
Log Message:	make some methods static as suggested by errorprone [MethodCanBeStatic]
#	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.Comparator;
12	import java.util.Iterator;
13	import java.util.NoSuchElementException;
14	import java.util.PriorityQueue;
15	import java.util.Queue;
16
17	import junit.framework.Test;
18
19	public class PriorityQueueTest extends JSR166TestCase {
20	public static void main(String[] args) {
21	main(suite(), args);
22	}
23	public static Test suite() {
24	class Implementation implements CollectionImplementation {
25	public Class<?> klazz() { return PriorityQueue.class; }
26	public Collection emptyCollection() { return new PriorityQueue(); }
27	public Object makeElement(int i) { return i; }
28	public boolean isConcurrent() { return false; }
29	public boolean permitsNulls() { return false; }
30	}
31	return newTestSuite(PriorityQueueTest.class,
32	CollectionTest.testSuite(new Implementation()));
33	}
34
35	static class MyReverseComparator implements Comparator {
36	public int compare(Object x, Object y) {
37	return ((Comparable)y).compareTo(x);
38	}
39	}
40
41	/**
42	* Returns a new queue of given size containing consecutive
43	* Integers 0 ... n - 1.
44	*/
45	private static PriorityQueue<Integer> populatedQueue(int n) {
46	PriorityQueue<Integer> q = new PriorityQueue<>(n);
47	assertTrue(q.isEmpty());
48	for (int i = n - 1; i >= 0; i -= 2)
49	assertTrue(q.offer(new Integer(i)));
50	for (int i = (n & 1); i < n; i += 2)
51	assertTrue(q.offer(new Integer(i)));
52	assertFalse(q.isEmpty());
53	assertEquals(n, q.size());
54	assertEquals((Integer) 0, q.peek());
55	return q;
56	}
57
58	/**
59	* A new queue has unbounded capacity
60	*/
61	public void testConstructor1() {
62	assertEquals(0, new PriorityQueue(SIZE).size());
63	}
64
65	/**
66	* Constructor throws IAE if capacity argument nonpositive
67	*/
68	public void testConstructor2() {
69	try {
70	new PriorityQueue(0);
71	shouldThrow();
72	} catch (IllegalArgumentException success) {}
73	}
74
75	/**
76	* Initializing from null Collection throws NPE
77	*/
78	public void testConstructor3() {
79	try {
80	new PriorityQueue((Collection)null);
81	shouldThrow();
82	} catch (NullPointerException success) {}
83	}
84
85	/**
86	* Initializing from Collection of null elements throws NPE
87	*/
88	public void testConstructor4() {
89	try {
90	new PriorityQueue(Arrays.asList(new Integer[SIZE]));
91	shouldThrow();
92	} catch (NullPointerException success) {}
93	}
94
95	/**
96	* Initializing from Collection with some null elements throws NPE
97	*/
98	public void testConstructor5() {
99	Integer[] ints = new Integer[SIZE];
100	for (int i = 0; i < SIZE - 1; ++i)
101	ints[i] = new Integer(i);
102	try {
103	new PriorityQueue(Arrays.asList(ints));
104	shouldThrow();
105	} catch (NullPointerException success) {}
106	}
107
108	/**
109	* Queue contains all elements of collection used to initialize
110	*/
111	public void testConstructor6() {
112	Integer[] ints = new Integer[SIZE];
113	for (int i = 0; i < SIZE; ++i)
114	ints[i] = new Integer(i);
115	PriorityQueue q = new PriorityQueue(Arrays.asList(ints));
116	for (int i = 0; i < SIZE; ++i)
117	assertEquals(ints[i], q.poll());
118	}
119
120	/**
121	* The comparator used in constructor is used
122	*/
123	public void testConstructor7() {
124	MyReverseComparator cmp = new MyReverseComparator();
125	PriorityQueue q = new PriorityQueue(SIZE, cmp);
126	assertEquals(cmp, q.comparator());
127	Integer[] ints = new Integer[SIZE];
128	for (int i = 0; i < SIZE; ++i)
129	ints[i] = new Integer(i);
130	q.addAll(Arrays.asList(ints));
131	for (int i = SIZE - 1; i >= 0; --i)
132	assertEquals(ints[i], q.poll());
133	}
134
135	/**
136	* isEmpty is true before add, false after
137	*/
138	public void testEmpty() {
139	PriorityQueue q = new PriorityQueue(2);
140	assertTrue(q.isEmpty());
141	q.add(new Integer(1));
142	assertFalse(q.isEmpty());
143	q.add(new Integer(2));
144	q.remove();
145	q.remove();
146	assertTrue(q.isEmpty());
147	}
148
149	/**
150	* size changes when elements added and removed
151	*/
152	public void testSize() {
153	PriorityQueue q = populatedQueue(SIZE);
154	for (int i = 0; i < SIZE; ++i) {
155	assertEquals(SIZE - i, q.size());
156	q.remove();
157	}
158	for (int i = 0; i < SIZE; ++i) {
159	assertEquals(i, q.size());
160	q.add(new Integer(i));
161	}
162	}
163
164	/**
165	* offer(null) throws NPE
166	*/
167	public void testOfferNull() {
168	PriorityQueue q = new PriorityQueue(1);
169	try {
170	q.offer(null);
171	shouldThrow();
172	} catch (NullPointerException success) {}
173	}
174
175	/**
176	* add(null) throws NPE
177	*/
178	public void testAddNull() {
179	PriorityQueue q = new PriorityQueue(1);
180	try {
181	q.add(null);
182	shouldThrow();
183	} catch (NullPointerException success) {}
184	}
185
186	/**
187	* Offer of comparable element succeeds
188	*/
189	public void testOffer() {
190	PriorityQueue q = new PriorityQueue(1);
191	assertTrue(q.offer(zero));
192	assertTrue(q.offer(one));
193	}
194
195	/**
196	* Offer of non-Comparable throws CCE
197	*/
198	public void testOfferNonComparable() {
199	PriorityQueue q = new PriorityQueue(1);
200	try {
201	q.offer(new Object());
202	shouldThrow();
203	} catch (ClassCastException success) {
204	assertTrue(q.isEmpty());
205	assertEquals(0, q.size());
206	assertNull(q.poll());
207	}
208	}
209
210	/**
211	* add of comparable succeeds
212	*/
213	public void testAdd() {
214	PriorityQueue q = new PriorityQueue(SIZE);
215	for (int i = 0; i < SIZE; ++i) {
216	assertEquals(i, q.size());
217	assertTrue(q.add(new Integer(i)));
218	}
219	}
220
221	/**
222	* addAll(null) throws NPE
223	*/
224	public void testAddAll1() {
225	PriorityQueue q = new PriorityQueue(1);
226	try {
227	q.addAll(null);
228	shouldThrow();
229	} catch (NullPointerException success) {}
230	}
231
232	/**
233	* addAll of a collection with null elements throws NPE
234	*/
235	public void testAddAll2() {
236	PriorityQueue q = new PriorityQueue(SIZE);
237	try {
238	q.addAll(Arrays.asList(new Integer[SIZE]));
239	shouldThrow();
240	} catch (NullPointerException success) {}
241	}
242
243	/**
244	* addAll of a collection with any null elements throws NPE after
245	* possibly adding some elements
246	*/
247	public void testAddAll3() {
248	PriorityQueue q = new PriorityQueue(SIZE);
249	Integer[] ints = new Integer[SIZE];
250	for (int i = 0; i < SIZE - 1; ++i)
251	ints[i] = new Integer(i);
252	try {
253	q.addAll(Arrays.asList(ints));
254	shouldThrow();
255	} catch (NullPointerException success) {}
256	}
257
258	/**
259	* Queue contains all elements of successful addAll
260	*/
261	public void testAddAll5() {
262	Integer[] empty = new Integer[0];
263	Integer[] ints = new Integer[SIZE];
264	for (int i = 0; i < SIZE; ++i)
265	ints[i] = new Integer(SIZE - 1 - i);
266	PriorityQueue q = new PriorityQueue(SIZE);
267	assertFalse(q.addAll(Arrays.asList(empty)));
268	assertTrue(q.addAll(Arrays.asList(ints)));
269	for (int i = 0; i < SIZE; ++i)
270	assertEquals(new Integer(i), q.poll());
271	}
272
273	/**
274	* poll succeeds unless empty
275	*/
276	public void testPoll() {
277	PriorityQueue q = populatedQueue(SIZE);
278	for (int i = 0; i < SIZE; ++i) {
279	assertEquals(i, q.poll());
280	}
281	assertNull(q.poll());
282	}
283
284	/**
285	* peek returns next element, or null if empty
286	*/
287	public void testPeek() {
288	PriorityQueue q = populatedQueue(SIZE);
289	for (int i = 0; i < SIZE; ++i) {
290	assertEquals(i, q.peek());
291	assertEquals(i, q.poll());
292	assertTrue(q.peek() == null \|\|
293	!q.peek().equals(i));
294	}
295	assertNull(q.peek());
296	}
297
298	/**
299	* element returns next element, or throws NSEE if empty
300	*/
301	public void testElement() {
302	PriorityQueue q = populatedQueue(SIZE);
303	for (int i = 0; i < SIZE; ++i) {
304	assertEquals(i, q.element());
305	assertEquals(i, q.poll());
306	}
307	try {
308	q.element();
309	shouldThrow();
310	} catch (NoSuchElementException success) {}
311	}
312
313	/**
314	* remove removes next element, or throws NSEE if empty
315	*/
316	public void testRemove() {
317	PriorityQueue q = populatedQueue(SIZE);
318	for (int i = 0; i < SIZE; ++i) {
319	assertEquals(i, q.remove());
320	}
321	try {
322	q.remove();
323	shouldThrow();
324	} catch (NoSuchElementException success) {}
325	}
326
327	/**
328	* remove(x) removes x and returns true if present
329	*/
330	public void testRemoveElement() {
331	PriorityQueue q = populatedQueue(SIZE);
332	for (int i = 1; i < SIZE; i += 2) {
333	assertTrue(q.contains(i));
334	assertTrue(q.remove(i));
335	assertFalse(q.contains(i));
336	assertTrue(q.contains(i - 1));
337	}
338	for (int i = 0; i < SIZE; i += 2) {
339	assertTrue(q.contains(i));
340	assertTrue(q.remove(i));
341	assertFalse(q.contains(i));
342	assertFalse(q.remove(i + 1));
343	assertFalse(q.contains(i + 1));
344	}
345	assertTrue(q.isEmpty());
346	}
347
348	/**
349	* contains(x) reports true when elements added but not yet removed
350	*/
351	public void testContains() {
352	PriorityQueue q = populatedQueue(SIZE);
353	for (int i = 0; i < SIZE; ++i) {
354	assertTrue(q.contains(new Integer(i)));
355	q.poll();
356	assertFalse(q.contains(new Integer(i)));
357	}
358	}
359
360	/**
361	* clear removes all elements
362	*/
363	public void testClear() {
364	PriorityQueue q = populatedQueue(SIZE);
365	q.clear();
366	assertTrue(q.isEmpty());
367	assertEquals(0, q.size());
368	q.add(new Integer(1));
369	assertFalse(q.isEmpty());
370	q.clear();
371	assertTrue(q.isEmpty());
372	}
373
374	/**
375	* containsAll(c) is true when c contains a subset of elements
376	*/
377	public void testContainsAll() {
378	PriorityQueue q = populatedQueue(SIZE);
379	PriorityQueue p = new PriorityQueue(SIZE);
380	for (int i = 0; i < SIZE; ++i) {
381	assertTrue(q.containsAll(p));
382	assertFalse(p.containsAll(q));
383	p.add(new Integer(i));
384	}
385	assertTrue(p.containsAll(q));
386	}
387
388	/**
389	* retainAll(c) retains only those elements of c and reports true if changed
390	*/
391	public void testRetainAll() {
392	PriorityQueue q = populatedQueue(SIZE);
393	PriorityQueue p = populatedQueue(SIZE);
394	for (int i = 0; i < SIZE; ++i) {
395	boolean changed = q.retainAll(p);
396	if (i == 0)
397	assertFalse(changed);
398	else
399	assertTrue(changed);
400
401	assertTrue(q.containsAll(p));
402	assertEquals(SIZE - i, q.size());
403	p.remove();
404	}
405	}
406
407	/**
408	* removeAll(c) removes only those elements of c and reports true if changed
409	*/
410	public void testRemoveAll() {
411	for (int i = 1; i < SIZE; ++i) {
412	PriorityQueue q = populatedQueue(SIZE);
413	PriorityQueue p = populatedQueue(i);
414	assertTrue(q.removeAll(p));
415	assertEquals(SIZE - i, q.size());
416	for (int j = 0; j < i; ++j) {
417	Integer x = (Integer)(p.remove());
418	assertFalse(q.contains(x));
419	}
420	}
421	}
422
423	/**
424	* toArray contains all elements
425	*/
426	public void testToArray() {
427	PriorityQueue q = populatedQueue(SIZE);
428	Object[] o = q.toArray();
429	Arrays.sort(o);
430	for (int i = 0; i < o.length; i++)
431	assertSame(o[i], q.poll());
432	}
433
434	/**
435	* toArray(a) contains all elements
436	*/
437	public void testToArray2() {
438	PriorityQueue<Integer> q = populatedQueue(SIZE);
439	Integer[] ints = new Integer[SIZE];
440	Integer[] array = q.toArray(ints);
441	assertSame(ints, array);
442	Arrays.sort(ints);
443	for (int i = 0; i < ints.length; i++)
444	assertSame(ints[i], q.poll());
445	}
446
447	/**
448	* iterator iterates through all elements
449	*/
450	public void testIterator() {
451	PriorityQueue q = populatedQueue(SIZE);
452	Iterator it = q.iterator();
453	int i;
454	for (i = 0; it.hasNext(); i++)
455	assertTrue(q.contains(it.next()));
456	assertEquals(i, SIZE);
457	assertIteratorExhausted(it);
458	}
459
460	/**
461	* iterator of empty collection has no elements
462	*/
463	public void testEmptyIterator() {
464	assertIteratorExhausted(new PriorityQueue().iterator());
465	}
466
467	/**
468	* iterator.remove removes current element
469	*/
470	public void testIteratorRemove() {
471	final PriorityQueue q = new PriorityQueue(3);
472	q.add(new Integer(2));
473	q.add(new Integer(1));
474	q.add(new Integer(3));
475
476	Iterator it = q.iterator();
477	it.next();
478	it.remove();
479
480	it = q.iterator();
481	assertEquals(it.next(), new Integer(2));
482	assertEquals(it.next(), new Integer(3));
483	assertFalse(it.hasNext());
484	}
485
486	/**
487	* toString contains toStrings of elements
488	*/
489	public void testToString() {
490	PriorityQueue 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	* A deserialized serialized queue has same elements
499	*/
500	public void testSerialization() throws Exception {
501	Queue x = populatedQueue(SIZE);
502	Queue y = serialClone(x);
503
504	assertNotSame(x, y);
505	assertEquals(x.size(), y.size());
506	while (!x.isEmpty()) {
507	assertFalse(y.isEmpty());
508	assertEquals(x.remove(), y.remove());
509	}
510	assertTrue(y.isEmpty());
511	}
512	}