001/* 002 * Copyright (C) 2007 The Guava Authors 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package com.google.common.collect.testing; 018 019import com.google.common.annotations.GwtCompatible; 020import com.google.errorprone.annotations.CanIgnoreReturnValue; 021import java.util.Collection; 022import org.checkerframework.checker.nullness.qual.Nullable; 023import org.junit.Ignore; 024 025/** 026 * Base class for collection testers. 027 * 028 * @param <E> the element type of the collection to be tested. 029 * @author Kevin Bourrillion 030 */ 031@GwtCompatible 032@Ignore("test runners must not instantiate and run this directly, only via suites we build") 033// @Ignore affects the Android test runner, which respects JUnit 4 annotations on JUnit 3 tests. 034@SuppressWarnings("JUnit4ClassUsedInJUnit3") 035@ElementTypesAreNonnullByDefault 036public abstract class AbstractCollectionTester<E extends @Nullable Object> 037 extends AbstractContainerTester<Collection<E>, E> { 038 039 // TODO: replace this with an accessor. 040 protected Collection<E> collection; 041 042 @Override 043 protected Collection<E> actualContents() { 044 return collection; 045 } 046 047 // TODO: dispose of this once collection is encapsulated. 048 @Override 049 @CanIgnoreReturnValue 050 protected Collection<E> resetContainer(Collection<E> newContents) { 051 collection = super.resetContainer(newContents); 052 return collection; 053 } 054 055 /** @see AbstractContainerTester#resetContainer() */ 056 protected void resetCollection() { 057 resetContainer(); 058 } 059 060 /** @return an array of the proper size with {@code null} inserted into the middle element. */ 061 protected E[] createArrayWithNullElement() { 062 E[] array = createSamplesArray(); 063 array[getNullLocation()] = null; 064 return array; 065 } 066 067 protected void initCollectionWithNullElement() { 068 E[] array = createArrayWithNullElement(); 069 resetContainer(getSubjectGenerator().create(array)); 070 } 071 072 /** 073 * Equivalent to {@link #expectMissing(Object[]) expectMissing}{@code (null)} except that the call 074 * to {@code contains(null)} is permitted to throw a {@code NullPointerException}. 075 * 076 * @param message message to use upon assertion failure 077 */ 078 protected void expectNullMissingWhenNullUnsupported(String message) { 079 try { 080 assertFalse(message, actualContents().contains(null)); 081 } catch (NullPointerException tolerated) { 082 // Tolerated 083 } 084 } 085}