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/* |
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* Written by Doug Lea and Martin Buchholz with assistance from |
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* members of JCP JSR-166 Expert Group and released to the public |
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* domain, as explained at |
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* http://creativecommons.org/publicdomain/zero/1.0/ |
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*/ |
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|
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import java.util.ArrayList; |
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import java.util.Collection; |
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import java.util.Collections; |
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import java.util.Deque; |
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import java.util.HashSet; |
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import java.util.Iterator; |
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import java.util.List; |
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import java.util.NoSuchElementException; |
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import java.util.Queue; |
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import java.util.Spliterator; |
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import java.util.concurrent.ThreadLocalRandom; |
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import java.util.concurrent.atomic.AtomicReference; |
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import java.util.function.Consumer; |
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import java.util.function.Predicate; |
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|
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import junit.framework.Test; |
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|
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/** |
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* Contains tests applicable to all Collection implementations. |
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*/ |
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public class CollectionTest extends JSR166TestCase { |
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final CollectionImplementation impl; |
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|
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/** Tests are parameterized by a Collection implementation. */ |
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CollectionTest(CollectionImplementation impl, String methodName) { |
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super(methodName); |
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this.impl = impl; |
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} |
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|
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public static Test testSuite(CollectionImplementation impl) { |
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return newTestSuite |
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(parameterizedTestSuite(CollectionTest.class, |
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CollectionImplementation.class, |
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impl), |
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jdk8ParameterizedTestSuite(CollectionTest.class, |
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CollectionImplementation.class, |
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impl)); |
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} |
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|
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/** Checks properties of empty collections. */ |
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public void testEmptyMeansEmpty() { |
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Collection c = impl.emptyCollection(); |
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assertTrue(c.isEmpty()); |
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assertEquals(0, c.size()); |
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assertEquals("[]", c.toString()); |
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{ |
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Object[] a = c.toArray(); |
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assertEquals(0, a.length); |
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assertSame(Object[].class, a.getClass()); |
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} |
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{ |
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Object[] a = new Object[0]; |
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assertSame(a, c.toArray(a)); |
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} |
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{ |
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Integer[] a = new Integer[0]; |
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assertSame(a, c.toArray(a)); |
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} |
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{ |
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Integer[] a = { 1, 2, 3}; |
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assertSame(a, c.toArray(a)); |
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assertNull(a[0]); |
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assertSame(2, a[1]); |
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assertSame(3, a[2]); |
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} |
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assertIteratorExhausted(c.iterator()); |
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Consumer alwaysThrows = (e) -> { throw new AssertionError(); }; |
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c.forEach(alwaysThrows); |
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c.iterator().forEachRemaining(alwaysThrows); |
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c.spliterator().forEachRemaining(alwaysThrows); |
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assertFalse(c.spliterator().tryAdvance(alwaysThrows)); |
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if (Queue.class.isAssignableFrom(impl.klazz())) { |
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Queue q = (Queue) c; |
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assertNull(q.peek()); |
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assertNull(q.poll()); |
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} |
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if (Deque.class.isAssignableFrom(impl.klazz())) { |
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Deque d = (Deque) c; |
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assertNull(d.peekFirst()); |
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assertNull(d.peekLast()); |
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assertNull(d.pollFirst()); |
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assertNull(d.pollLast()); |
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assertIteratorExhausted(d.descendingIterator()); |
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} |
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} |
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|
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public void testNullPointerExceptions() { |
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Collection c = impl.emptyCollection(); |
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assertThrows( |
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NullPointerException.class, |
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() -> c.addAll(null), |
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() -> c.containsAll(null), |
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() -> c.retainAll(null), |
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() -> c.removeAll(null), |
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() -> c.removeIf(null), |
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() -> c.toArray(null)); |
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|
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if (!impl.permitsNulls()) { |
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assertThrows( |
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NullPointerException.class, |
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() -> c.add(null)); |
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} |
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if (!impl.permitsNulls() |
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&& Queue.class.isAssignableFrom(impl.klazz())) { |
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Queue q = (Queue) c; |
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assertThrows( |
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NullPointerException.class, |
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() -> q.offer(null)); |
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} |
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if (!impl.permitsNulls() |
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&& Deque.class.isAssignableFrom(impl.klazz())) { |
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Deque d = (Deque) c; |
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assertThrows( |
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NullPointerException.class, |
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() -> d.addFirst(null), |
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() -> d.addLast(null), |
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() -> d.offerFirst(null), |
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() -> d.offerLast(null), |
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() -> d.push(null)); |
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} |
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} |
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|
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public void testNoSuchElementExceptions() { |
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Collection c = impl.emptyCollection(); |
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assertThrows( |
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NoSuchElementException.class, |
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() -> c.iterator().next()); |
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|
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if (Queue.class.isAssignableFrom(impl.klazz())) { |
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Queue q = (Queue) c; |
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assertThrows( |
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NoSuchElementException.class, |
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() -> q.element(), |
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() -> q.remove()); |
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} |
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if (Deque.class.isAssignableFrom(impl.klazz())) { |
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Deque d = (Deque) c; |
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assertThrows( |
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NoSuchElementException.class, |
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() -> d.getFirst(), |
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() -> d.getLast(), |
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() -> d.removeFirst(), |
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() -> d.removeLast(), |
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() -> d.pop(), |
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() -> d.descendingIterator().next()); |
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} |
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} |
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|
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public void testRemoveIf() { |
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Collection c = impl.emptyCollection(); |
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ThreadLocalRandom rnd = ThreadLocalRandom.current(); |
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int n = rnd.nextInt(6); |
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for (int i = 0; i < n; i++) c.add(impl.makeElement(i)); |
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AtomicReference threwAt = new AtomicReference(null); |
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ArrayList survivors = new ArrayList(c); |
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ArrayList accepts = new ArrayList(); |
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ArrayList rejects = new ArrayList(); |
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Predicate randomPredicate = (e) -> { |
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assertNull(threwAt.get()); |
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switch (rnd.nextInt(3)) { |
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case 0: accepts.add(e); return true; |
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case 1: rejects.add(e); return false; |
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case 2: threwAt.set(e); throw new ArithmeticException(); |
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default: throw new AssertionError(); |
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} |
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}; |
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try { |
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boolean modified = c.removeIf(randomPredicate); |
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if (!modified) { |
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assertNull(threwAt.get()); |
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assertEquals(n, rejects.size()); |
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assertEquals(0, accepts.size()); |
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} |
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} catch (ArithmeticException ok) {} |
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survivors.removeAll(accepts); |
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if (n - accepts.size() != c.size()) { |
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System.err.println(impl.klazz()); |
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System.err.println(c); |
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System.err.println(accepts); |
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System.err.println(rejects); |
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System.err.println(survivors); |
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System.err.println(threwAt.get()); |
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} |
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assertEquals(n - accepts.size(), c.size()); |
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assertTrue(c.containsAll(survivors)); |
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assertTrue(survivors.containsAll(rejects)); |
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for (Object x : accepts) assertFalse(c.contains(x)); |
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if (threwAt.get() == null) |
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assertEquals(accepts.size() + rejects.size(), n); |
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} |
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|
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/** |
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* Various ways of traversing a collection yield same elements |
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*/ |
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public void testIteratorEquivalence() { |
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Collection c = impl.emptyCollection(); |
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ThreadLocalRandom rnd = ThreadLocalRandom.current(); |
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int n = rnd.nextInt(6); |
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for (int i = 0; i < n; i++) c.add(impl.makeElement(i)); |
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ArrayList iterated = new ArrayList(); |
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ArrayList iteratedForEachRemaining = new ArrayList(); |
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ArrayList spliterated = new ArrayList(); |
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ArrayList foreached = new ArrayList(); |
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for (Object x : c) iterated.add(x); |
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c.iterator().forEachRemaining(e -> iteratedForEachRemaining.add(e)); |
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c.spliterator().forEachRemaining(e -> spliterated.add(e)); |
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c.forEach(e -> foreached.add(e)); |
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boolean ordered = |
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c.spliterator().hasCharacteristics(Spliterator.ORDERED); |
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if (c instanceof List || c instanceof Deque) |
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assertTrue(ordered); |
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if (ordered) { |
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assertEquals(iterated, iteratedForEachRemaining); |
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assertEquals(iterated, spliterated); |
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assertEquals(iterated, foreached); |
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} else { |
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HashSet cset = new HashSet(c); |
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assertEquals(cset, new HashSet(iterated)); |
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assertEquals(cset, new HashSet(iteratedForEachRemaining)); |
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assertEquals(cset, new HashSet(spliterated)); |
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assertEquals(cset, new HashSet(foreached)); |
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} |
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if (c instanceof Deque) { |
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Deque d = (Deque) c; |
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ArrayList descending = new ArrayList(); |
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ArrayList descendingForEachRemaining = new ArrayList(); |
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for (Iterator it = d.descendingIterator(); it.hasNext(); ) |
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descending.add(it.next()); |
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d.descendingIterator().forEachRemaining( |
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e -> descendingForEachRemaining.add(e)); |
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Collections.reverse(descending); |
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Collections.reverse(descendingForEachRemaining); |
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assertEquals(iterated, descending); |
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assertEquals(iterated, descendingForEachRemaining); |
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} |
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} |
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|
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/** |
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* Calling Iterator#remove() after Iterator#forEachRemaining |
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* should remove last element |
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*/ |
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public void testRemoveAfterForEachRemaining() { |
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Collection c = impl.emptyCollection(); |
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ThreadLocalRandom rnd = ThreadLocalRandom.current(); |
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{ |
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int n = 3 + rnd.nextInt(2); |
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for (int i = 0; i < n; i++) c.add(impl.makeElement(i)); |
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Iterator it = c.iterator(); |
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assertTrue(it.hasNext()); |
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assertEquals(impl.makeElement(0), it.next()); |
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assertTrue(it.hasNext()); |
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assertEquals(impl.makeElement(1), it.next()); |
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it.forEachRemaining((e) -> {}); |
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it.remove(); |
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assertEquals(n - 1, c.size()); |
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for (int i = 0; i < n - 1; i++) |
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assertTrue(c.contains(impl.makeElement(i))); |
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assertFalse(c.contains(impl.makeElement(n - 1))); |
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} |
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if (c instanceof Deque) { |
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Deque d = (Deque) impl.emptyCollection(); |
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int n = 3 + rnd.nextInt(2); |
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for (int i = 0; i < n; i++) d.add(impl.makeElement(i)); |
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Iterator it = d.descendingIterator(); |
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assertTrue(it.hasNext()); |
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assertEquals(impl.makeElement(n - 1), it.next()); |
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assertTrue(it.hasNext()); |
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assertEquals(impl.makeElement(n - 2), it.next()); |
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it.forEachRemaining((e) -> {}); |
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it.remove(); |
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assertEquals(n - 1, d.size()); |
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for (int i = 1; i < n; i++) |
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assertTrue(d.contains(impl.makeElement(i))); |
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assertFalse(d.contains(impl.makeElement(0))); |
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} |
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} |
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|
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// public void testCollectionDebugFail() { |
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// fail(impl.klazz().getSimpleName()); |
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// } |
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} |
