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; }
        }
        class ComparatorImplementation implements CollectionImplementation {
            public Class<?> klazz() { return PriorityQueue.class; }
            public Collection emptyCollection() {
                return new PriorityQueue(new MyReverseComparator());
            }
            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()),
            CollectionTest.testSuite(new ComparatorImplementation()));
    }

    static class MyReverseComparator implements Comparator, java.io.Serializable {
        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 IllegalArgumentException 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[] a = q.toArray();
        assertSame(Object[].class, a.getClass());
        Arrays.sort(a);
        for (Object o : a)
            assertSame(o, q.poll());
        assertTrue(q.isEmpty());
    }

    /**
     * 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 (Integer o : ints)
            assertSame(o, q.poll());
        assertTrue(q.isEmpty());
    }

    /**
     * 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/reserialized 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:	1.47
Committed:	Mon May 28 21:19:50 2018 UTC (5 years, 11 months ago) by jsr166
Branch:	MAIN
Changes since 1.46:	+9 -6 lines
Log Message:	improve toArray tests
#	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	class ComparatorImplementation implements CollectionImplementation {
32	public Class<?> klazz() { return PriorityQueue.class; }
33	public Collection emptyCollection() {
34	return new PriorityQueue(new MyReverseComparator());
35	}
36	public Object makeElement(int i) { return i; }
37	public boolean isConcurrent() { return false; }
38	public boolean permitsNulls() { return false; }
39	}
40	return newTestSuite(
41	PriorityQueueTest.class,
42	CollectionTest.testSuite(new Implementation()),
43	CollectionTest.testSuite(new ComparatorImplementation()));
44	}
45
46	static class MyReverseComparator implements Comparator, java.io.Serializable {
47	public int compare(Object x, Object y) {
48	return ((Comparable)y).compareTo(x);
49	}
50	}
51
52	/**
53	* Returns a new queue of given size containing consecutive
54	* Integers 0 ... n - 1.
55	*/
56	private static PriorityQueue<Integer> populatedQueue(int n) {
57	PriorityQueue<Integer> q = new PriorityQueue<>(n);
58	assertTrue(q.isEmpty());
59	for (int i = n - 1; i >= 0; i -= 2)
60	assertTrue(q.offer(new Integer(i)));
61	for (int i = (n & 1); i < n; i += 2)
62	assertTrue(q.offer(new Integer(i)));
63	assertFalse(q.isEmpty());
64	assertEquals(n, q.size());
65	assertEquals((Integer) 0, q.peek());
66	return q;
67	}
68
69	/**
70	* A new queue has unbounded capacity
71	*/
72	public void testConstructor1() {
73	assertEquals(0, new PriorityQueue(SIZE).size());
74	}
75
76	/**
77	* Constructor throws IllegalArgumentException if capacity argument nonpositive
78	*/
79	public void testConstructor2() {
80	try {
81	new PriorityQueue(0);
82	shouldThrow();
83	} catch (IllegalArgumentException success) {}
84	}
85
86	/**
87	* Initializing from null Collection throws NPE
88	*/
89	public void testConstructor3() {
90	try {
91	new PriorityQueue((Collection)null);
92	shouldThrow();
93	} catch (NullPointerException success) {}
94	}
95
96	/**
97	* Initializing from Collection of null elements throws NPE
98	*/
99	public void testConstructor4() {
100	try {
101	new PriorityQueue(Arrays.asList(new Integer[SIZE]));
102	shouldThrow();
103	} catch (NullPointerException success) {}
104	}
105
106	/**
107	* Initializing from Collection with some null elements throws NPE
108	*/
109	public void testConstructor5() {
110	Integer[] ints = new Integer[SIZE];
111	for (int i = 0; i < SIZE - 1; ++i)
112	ints[i] = new Integer(i);
113	try {
114	new PriorityQueue(Arrays.asList(ints));
115	shouldThrow();
116	} catch (NullPointerException success) {}
117	}
118
119	/**
120	* Queue contains all elements of collection used to initialize
121	*/
122	public void testConstructor6() {
123	Integer[] ints = new Integer[SIZE];
124	for (int i = 0; i < SIZE; ++i)
125	ints[i] = new Integer(i);
126	PriorityQueue q = new PriorityQueue(Arrays.asList(ints));
127	for (int i = 0; i < SIZE; ++i)
128	assertEquals(ints[i], q.poll());
129	}
130
131	/**
132	* The comparator used in constructor is used
133	*/
134	public void testConstructor7() {
135	MyReverseComparator cmp = new MyReverseComparator();
136	PriorityQueue q = new PriorityQueue(SIZE, cmp);
137	assertEquals(cmp, q.comparator());
138	Integer[] ints = new Integer[SIZE];
139	for (int i = 0; i < SIZE; ++i)
140	ints[i] = new Integer(i);
141	q.addAll(Arrays.asList(ints));
142	for (int i = SIZE - 1; i >= 0; --i)
143	assertEquals(ints[i], q.poll());
144	}
145
146	/**
147	* isEmpty is true before add, false after
148	*/
149	public void testEmpty() {
150	PriorityQueue q = new PriorityQueue(2);
151	assertTrue(q.isEmpty());
152	q.add(new Integer(1));
153	assertFalse(q.isEmpty());
154	q.add(new Integer(2));
155	q.remove();
156	q.remove();
157	assertTrue(q.isEmpty());
158	}
159
160	/**
161	* size changes when elements added and removed
162	*/
163	public void testSize() {
164	PriorityQueue q = populatedQueue(SIZE);
165	for (int i = 0; i < SIZE; ++i) {
166	assertEquals(SIZE - i, q.size());
167	q.remove();
168	}
169	for (int i = 0; i < SIZE; ++i) {
170	assertEquals(i, q.size());
171	q.add(new Integer(i));
172	}
173	}
174
175	/**
176	* offer(null) throws NPE
177	*/
178	public void testOfferNull() {
179	PriorityQueue q = new PriorityQueue(1);
180	try {
181	q.offer(null);
182	shouldThrow();
183	} catch (NullPointerException success) {}
184	}
185
186	/**
187	* add(null) throws NPE
188	*/
189	public void testAddNull() {
190	PriorityQueue q = new PriorityQueue(1);
191	try {
192	q.add(null);
193	shouldThrow();
194	} catch (NullPointerException success) {}
195	}
196
197	/**
198	* Offer of comparable element succeeds
199	*/
200	public void testOffer() {
201	PriorityQueue q = new PriorityQueue(1);
202	assertTrue(q.offer(zero));
203	assertTrue(q.offer(one));
204	}
205
206	/**
207	* Offer of non-Comparable throws CCE
208	*/
209	public void testOfferNonComparable() {
210	PriorityQueue q = new PriorityQueue(1);
211	try {
212	q.offer(new Object());
213	shouldThrow();
214	} catch (ClassCastException success) {
215	assertTrue(q.isEmpty());
216	assertEquals(0, q.size());
217	assertNull(q.poll());
218	}
219	}
220
221	/**
222	* add of comparable succeeds
223	*/
224	public void testAdd() {
225	PriorityQueue q = new PriorityQueue(SIZE);
226	for (int i = 0; i < SIZE; ++i) {
227	assertEquals(i, q.size());
228	assertTrue(q.add(new Integer(i)));
229	}
230	}
231
232	/**
233	* addAll(null) throws NPE
234	*/
235	public void testAddAll1() {
236	PriorityQueue q = new PriorityQueue(1);
237	try {
238	q.addAll(null);
239	shouldThrow();
240	} catch (NullPointerException success) {}
241	}
242
243	/**
244	* addAll of a collection with null elements throws NPE
245	*/
246	public void testAddAll2() {
247	PriorityQueue q = new PriorityQueue(SIZE);
248	try {
249	q.addAll(Arrays.asList(new Integer[SIZE]));
250	shouldThrow();
251	} catch (NullPointerException success) {}
252	}
253
254	/**
255	* addAll of a collection with any null elements throws NPE after
256	* possibly adding some elements
257	*/
258	public void testAddAll3() {
259	PriorityQueue q = new PriorityQueue(SIZE);
260	Integer[] ints = new Integer[SIZE];
261	for (int i = 0; i < SIZE - 1; ++i)
262	ints[i] = new Integer(i);
263	try {
264	q.addAll(Arrays.asList(ints));
265	shouldThrow();
266	} catch (NullPointerException success) {}
267	}
268
269	/**
270	* Queue contains all elements of successful addAll
271	*/
272	public void testAddAll5() {
273	Integer[] empty = new Integer[0];
274	Integer[] ints = new Integer[SIZE];
275	for (int i = 0; i < SIZE; ++i)
276	ints[i] = new Integer(SIZE - 1 - i);
277	PriorityQueue q = new PriorityQueue(SIZE);
278	assertFalse(q.addAll(Arrays.asList(empty)));
279	assertTrue(q.addAll(Arrays.asList(ints)));
280	for (int i = 0; i < SIZE; ++i)
281	assertEquals(new Integer(i), q.poll());
282	}
283
284	/**
285	* poll succeeds unless empty
286	*/
287	public void testPoll() {
288	PriorityQueue q = populatedQueue(SIZE);
289	for (int i = 0; i < SIZE; ++i) {
290	assertEquals(i, q.poll());
291	}
292	assertNull(q.poll());
293	}
294
295	/**
296	* peek returns next element, or null if empty
297	*/
298	public void testPeek() {
299	PriorityQueue q = populatedQueue(SIZE);
300	for (int i = 0; i < SIZE; ++i) {
301	assertEquals(i, q.peek());
302	assertEquals(i, q.poll());
303	assertTrue(q.peek() == null \|\|
304	!q.peek().equals(i));
305	}
306	assertNull(q.peek());
307	}
308
309	/**
310	* element returns next element, or throws NSEE if empty
311	*/
312	public void testElement() {
313	PriorityQueue q = populatedQueue(SIZE);
314	for (int i = 0; i < SIZE; ++i) {
315	assertEquals(i, q.element());
316	assertEquals(i, q.poll());
317	}
318	try {
319	q.element();
320	shouldThrow();
321	} catch (NoSuchElementException success) {}
322	}
323
324	/**
325	* remove removes next element, or throws NSEE if empty
326	*/
327	public void testRemove() {
328	PriorityQueue q = populatedQueue(SIZE);
329	for (int i = 0; i < SIZE; ++i) {
330	assertEquals(i, q.remove());
331	}
332	try {
333	q.remove();
334	shouldThrow();
335	} catch (NoSuchElementException success) {}
336	}
337
338	/**
339	* remove(x) removes x and returns true if present
340	*/
341	public void testRemoveElement() {
342	PriorityQueue q = populatedQueue(SIZE);
343	for (int i = 1; i < SIZE; i += 2) {
344	assertTrue(q.contains(i));
345	assertTrue(q.remove(i));
346	assertFalse(q.contains(i));
347	assertTrue(q.contains(i - 1));
348	}
349	for (int i = 0; i < SIZE; i += 2) {
350	assertTrue(q.contains(i));
351	assertTrue(q.remove(i));
352	assertFalse(q.contains(i));
353	assertFalse(q.remove(i + 1));
354	assertFalse(q.contains(i + 1));
355	}
356	assertTrue(q.isEmpty());
357	}
358
359	/**
360	* contains(x) reports true when elements added but not yet removed
361	*/
362	public void testContains() {
363	PriorityQueue q = populatedQueue(SIZE);
364	for (int i = 0; i < SIZE; ++i) {
365	assertTrue(q.contains(new Integer(i)));
366	q.poll();
367	assertFalse(q.contains(new Integer(i)));
368	}
369	}
370
371	/**
372	* clear removes all elements
373	*/
374	public void testClear() {
375	PriorityQueue q = populatedQueue(SIZE);
376	q.clear();
377	assertTrue(q.isEmpty());
378	assertEquals(0, q.size());
379	q.add(new Integer(1));
380	assertFalse(q.isEmpty());
381	q.clear();
382	assertTrue(q.isEmpty());
383	}
384
385	/**
386	* containsAll(c) is true when c contains a subset of elements
387	*/
388	public void testContainsAll() {
389	PriorityQueue q = populatedQueue(SIZE);
390	PriorityQueue p = new PriorityQueue(SIZE);
391	for (int i = 0; i < SIZE; ++i) {
392	assertTrue(q.containsAll(p));
393	assertFalse(p.containsAll(q));
394	p.add(new Integer(i));
395	}
396	assertTrue(p.containsAll(q));
397	}
398
399	/**
400	* retainAll(c) retains only those elements of c and reports true if changed
401	*/
402	public void testRetainAll() {
403	PriorityQueue q = populatedQueue(SIZE);
404	PriorityQueue p = populatedQueue(SIZE);
405	for (int i = 0; i < SIZE; ++i) {
406	boolean changed = q.retainAll(p);
407	if (i == 0)
408	assertFalse(changed);
409	else
410	assertTrue(changed);
411
412	assertTrue(q.containsAll(p));
413	assertEquals(SIZE - i, q.size());
414	p.remove();
415	}
416	}
417
418	/**
419	* removeAll(c) removes only those elements of c and reports true if changed
420	*/
421	public void testRemoveAll() {
422	for (int i = 1; i < SIZE; ++i) {
423	PriorityQueue q = populatedQueue(SIZE);
424	PriorityQueue p = populatedQueue(i);
425	assertTrue(q.removeAll(p));
426	assertEquals(SIZE - i, q.size());
427	for (int j = 0; j < i; ++j) {
428	Integer x = (Integer)(p.remove());
429	assertFalse(q.contains(x));
430	}
431	}
432	}
433
434	/**
435	* toArray contains all elements
436	*/
437	public void testToArray() {
438	PriorityQueue q = populatedQueue(SIZE);
439	Object[] a = q.toArray();
440	assertSame(Object[].class, a.getClass());
441	Arrays.sort(a);
442	for (Object o : a)
443	assertSame(o, q.poll());
444	assertTrue(q.isEmpty());
445	}
446
447	/**
448	* toArray(a) contains all elements
449	*/
450	public void testToArray2() {
451	PriorityQueue<Integer> q = populatedQueue(SIZE);
452	Integer[] ints = new Integer[SIZE];
453	Integer[] array = q.toArray(ints);
454	assertSame(ints, array);
455	Arrays.sort(ints);
456	for (Integer o : ints)
457	assertSame(o, q.poll());
458	assertTrue(q.isEmpty());
459	}
460
461	/**
462	* iterator iterates through all elements
463	*/
464	public void testIterator() {
465	PriorityQueue q = populatedQueue(SIZE);
466	Iterator it = q.iterator();
467	int i;
468	for (i = 0; it.hasNext(); i++)
469	assertTrue(q.contains(it.next()));
470	assertEquals(i, SIZE);
471	assertIteratorExhausted(it);
472	}
473
474	/**
475	* iterator of empty collection has no elements
476	*/
477	public void testEmptyIterator() {
478	assertIteratorExhausted(new PriorityQueue().iterator());
479	}
480
481	/**
482	* iterator.remove removes current element
483	*/
484	public void testIteratorRemove() {
485	final PriorityQueue q = new PriorityQueue(3);
486	q.add(new Integer(2));
487	q.add(new Integer(1));
488	q.add(new Integer(3));
489
490	Iterator it = q.iterator();
491	it.next();
492	it.remove();
493
494	it = q.iterator();
495	assertEquals(it.next(), new Integer(2));
496	assertEquals(it.next(), new Integer(3));
497	assertFalse(it.hasNext());
498	}
499
500	/**
501	* toString contains toStrings of elements
502	*/
503	public void testToString() {
504	PriorityQueue q = populatedQueue(SIZE);
505	String s = q.toString();
506	for (int i = 0; i < SIZE; ++i) {
507	assertTrue(s.contains(String.valueOf(i)));
508	}
509	}
510
511	/**
512	* A deserialized/reserialized queue has same elements
513	*/
514	public void testSerialization() throws Exception {
515	Queue x = populatedQueue(SIZE);
516	Queue y = serialClone(x);
517
518	assertNotSame(x, y);
519	assertEquals(x.size(), y.size());
520	while (!x.isEmpty()) {
521	assertFalse(y.isEmpty());
522	assertEquals(x.remove(), y.remove());
523	}
524	assertTrue(y.isEmpty());
525	}
526	}