1 /* 2 * Copyright (C) 2008 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.common.collect.testing.testers; 18 19 import static com.google.common.collect.testing.features.CollectionFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION; 20 import static com.google.common.collect.testing.features.CollectionFeature.SUPPORTS_REMOVE; 21 import static com.google.common.collect.testing.features.CollectionSize.SEVERAL; 22 import static com.google.common.collect.testing.features.CollectionSize.ZERO; 23 24 import com.google.common.annotations.GwtCompatible; 25 import com.google.common.collect.testing.AbstractCollectionTester; 26 import com.google.common.collect.testing.features.CollectionFeature; 27 import com.google.common.collect.testing.features.CollectionSize; 28 29 import java.util.ConcurrentModificationException; 30 import java.util.Iterator; 31 32 /** 33 * A generic JUnit test which tests {@code clear()} operations on a collection. 34 * Can't be invoked directly; please see 35 * {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}. 36 * 37 * @author George van den Driessche 38 */ 39 @GwtCompatible 40 public class CollectionClearTester<E> extends AbstractCollectionTester<E> { 41 @CollectionFeature.Require(SUPPORTS_REMOVE) 42 public void testClear() { 43 collection.clear(); 44 assertTrue("After clear(), a collection should be empty.", 45 collection.isEmpty()); 46 } 47 48 @CollectionFeature.Require(absent = SUPPORTS_REMOVE) 49 @CollectionSize.Require(absent = ZERO) 50 public void testClear_unsupported() { 51 try { 52 collection.clear(); 53 fail("clear() should throw UnsupportedOperation if a collection does " 54 + "not support it and is not empty."); 55 } catch (UnsupportedOperationException expected) { 56 } 57 expectUnchanged(); 58 } 59 60 @CollectionFeature.Require(absent = SUPPORTS_REMOVE) 61 @CollectionSize.Require(ZERO) 62 public void testClear_unsupportedByEmptyCollection() { 63 try { 64 collection.clear(); 65 } catch (UnsupportedOperationException tolerated) { 66 } 67 expectUnchanged(); 68 } 69 70 @CollectionFeature.Require({SUPPORTS_REMOVE, 71 FAILS_FAST_ON_CONCURRENT_MODIFICATION}) 72 @CollectionSize.Require(SEVERAL) 73 public void testClearConcurrentWithIteration() { 74 try { 75 Iterator<E> iterator = collection.iterator(); 76 collection.clear(); 77 iterator.next(); 78 /* 79 * We prefer for iterators to fail immediately on hasNext, but ArrayList 80 * and LinkedList will notably return true on hasNext here! 81 */ 82 fail("Expected ConcurrentModificationException"); 83 } catch (ConcurrentModificationException expected) { 84 // success 85 } 86 } 87 } 88
