Coverage Summary for Class: ListHashCodeTester (com.google.common.collect.testing.testers)

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 com.google.common.annotations.GwtCompatible;
20 import com.google.common.annotations.GwtIncompatible;
21 import com.google.common.collect.testing.Helpers;
22 import java.lang.reflect.Method;
23 import org.junit.Ignore;
24 
25 /**
26  * Tests {@link java.util.List#hashCode}.
27  *
28  * @author George van den Driessche
29  */
30 @GwtCompatible(emulated = true)
31 @Ignore // Affects only Android test runner, which respects JUnit 4 annotations on JUnit 3 tests.
32 public class ListHashCodeTester<E> extends AbstractListTester<E> {
33   public void testHashCode() {
34     int expectedHashCode = 1;
35     for (E element : getOrderedElements()) {
36       expectedHashCode = 31 * expectedHashCode + ((element == null) ? 0 : element.hashCode());
37     }
38     assertEquals(
39         "A List's hashCode() should be computed from those of its elements.",
40         expectedHashCode,
41         getList().hashCode());
42   }
43 
44   /**
45    * Returns the {@link Method} instance for {@link #testHashCode()} so that list tests on
46    * unhashable objects can suppress it with {@code FeatureSpecificTestSuiteBuilder.suppressing()}.
47    */
48   @GwtIncompatible // reflection
49   public static Method getHashCodeMethod() {
50     return Helpers.getMethod(ListHashCodeTester.class, "testHashCode");
51   }
52 }