| /* |
| * Copyright (C) 2008 The Guava Authors |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.google.common.collect.testing.testers; |
| |
| import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEYS; |
| import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_VALUES; |
| |
| import com.google.common.annotations.GwtCompatible; |
| import com.google.common.collect.testing.AbstractMapTester; |
| import com.google.common.collect.testing.features.CollectionSize; |
| import com.google.common.collect.testing.features.MapFeature; |
| import java.util.Collection; |
| import java.util.Map.Entry; |
| import org.junit.Ignore; |
| |
| /** |
| * Tests {@link java.util.Map#hashCode}. |
| * |
| * @author George van den Driessche |
| * @author Chris Povirk |
| */ |
| @GwtCompatible |
| @Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests. |
| public class MapHashCodeTester<K, V> extends AbstractMapTester<K, V> { |
| public void testHashCode() { |
| int expectedHashCode = 0; |
| for (Entry<K, V> entry : getSampleEntries()) { |
| expectedHashCode += hash(entry); |
| } |
| assertEquals( |
| "A Map's hashCode() should be the sum of those of its entries.", |
| expectedHashCode, |
| getMap().hashCode()); |
| } |
| |
| @CollectionSize.Require(absent = CollectionSize.ZERO) |
| @MapFeature.Require(ALLOWS_NULL_KEYS) |
| public void testHashCode_containingNullKey() { |
| Entry<K, V> entryWithNull = entry(null, v3()); |
| runEntryWithNullTest(entryWithNull); |
| } |
| |
| @CollectionSize.Require(absent = CollectionSize.ZERO) |
| @MapFeature.Require(ALLOWS_NULL_VALUES) |
| public void testHashCode_containingNullValue() { |
| Entry<K, V> entryWithNull = entry(k3(), null); |
| runEntryWithNullTest(entryWithNull); |
| } |
| |
| private void runEntryWithNullTest(Entry<K, V> entryWithNull) { |
| Collection<Entry<K, V>> entries = getSampleEntries(getNumEntries() - 1); |
| |
| entries.add(entryWithNull); |
| |
| int expectedHashCode = 0; |
| for (Entry<K, V> entry : entries) { |
| expectedHashCode += hash(entry); |
| } |
| |
| resetContainer(getSubjectGenerator().create(entries.toArray())); |
| assertEquals( |
| "A Map's hashCode() should be the sum of those of its entries (where " |
| + "a null element in an entry counts as having a hash of zero).", |
| expectedHashCode, |
| getMap().hashCode()); |
| } |
| |
| private static int hash(Entry<?, ?> e) { |
| return (e.getKey() == null ? 0 : e.getKey().hashCode()) |
| ^ (e.getValue() == null ? 0 : e.getValue().hashCode()); |
| } |
| } |