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 import java.util.ConcurrentModificationException; 29 import java.util.Iterator; 30 import org.junit.Ignore; 31 32 /** 33 * A generic JUnit test which tests {@code clear()} operations on a collection. Can't be invoked 34 * directly; please see {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}. 35 * 36 * @author George van den Driessche 37 */ 38 @GwtCompatible 39 @Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests. 40 public class CollectionClearTester<E> extends AbstractCollectionTester<E> { 41 @CollectionFeature.Require(SUPPORTS_REMOVE) testClear()42 public void testClear() { 43 collection.clear(); 44 assertTrue("After clear(), a collection should be empty.", collection.isEmpty()); 45 assertEquals(0, collection.size()); 46 assertFalse(collection.iterator().hasNext()); 47 } 48 49 @CollectionFeature.Require(absent = SUPPORTS_REMOVE) 50 @CollectionSize.Require(absent = ZERO) testClear_unsupported()51 public void testClear_unsupported() { 52 try { 53 collection.clear(); 54 fail( 55 "clear() should throw UnsupportedOperation if a collection does " 56 + "not support it and is not empty."); 57 } catch (UnsupportedOperationException expected) { 58 } 59 expectUnchanged(); 60 } 61 62 @CollectionFeature.Require(absent = SUPPORTS_REMOVE) 63 @CollectionSize.Require(ZERO) testClear_unsupportedByEmptyCollection()64 public void testClear_unsupportedByEmptyCollection() { 65 try { 66 collection.clear(); 67 } catch (UnsupportedOperationException tolerated) { 68 } 69 expectUnchanged(); 70 } 71 72 @CollectionFeature.Require({SUPPORTS_REMOVE, FAILS_FAST_ON_CONCURRENT_MODIFICATION}) 73 @CollectionSize.Require(SEVERAL) testClearConcurrentWithIteration()74 public void testClearConcurrentWithIteration() { 75 try { 76 Iterator<E> iterator = collection.iterator(); 77 collection.clear(); 78 iterator.next(); 79 /* 80 * We prefer for iterators to fail immediately on hasNext, but ArrayList 81 * and LinkedList will notably return true on hasNext here! 82 */ 83 fail("Expected ConcurrentModificationException"); 84 } catch (ConcurrentModificationException expected) { 85 // success 86 } 87 } 88 } 89