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1 /*
2  * Copyright (C) 2011 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.hash;
18 
19 import static com.google.common.hash.Hashing.murmur3_32;
20 
21 import com.google.common.hash.HashTestUtils.HashFn;
22 
23 import junit.framework.TestCase;
24 
25 /**
26  * Tests for {@link Murmur3_32HashFunction}.
27  */
28 public class Murmur3Hash32Test extends TestCase {
testKnownIntegerInputs()29   public void testKnownIntegerInputs() {
30     assertHash(593689054, murmur3_32().hashInt(0));
31     assertHash(-189366624, murmur3_32().hashInt(-42));
32     assertHash(-1134849565, murmur3_32().hashInt(42));
33     assertHash(-1718298732, murmur3_32().hashInt(Integer.MIN_VALUE));
34     assertHash(-1653689534, murmur3_32().hashInt(Integer.MAX_VALUE));
35   }
36 
testKnownLongInputs()37   public void testKnownLongInputs() {
38     assertHash(1669671676, murmur3_32().hashLong(0L));
39     assertHash(-846261623, murmur3_32().hashLong(-42L));
40     assertHash(1871679806, murmur3_32().hashLong(42L));
41     assertHash(1366273829, murmur3_32().hashLong(Long.MIN_VALUE));
42     assertHash(-2106506049, murmur3_32().hashLong(Long.MAX_VALUE));
43   }
44 
testKnownStringInputs()45   public void testKnownStringInputs() {
46     assertHash(0, murmur3_32().hashUnencodedChars(""));
47     assertHash(679745764, murmur3_32().hashUnencodedChars("k"));
48     assertHash(1510782915, murmur3_32().hashUnencodedChars("hell"));
49     assertHash(-675079799, murmur3_32().hashUnencodedChars("hello"));
50     assertHash(1935035788, murmur3_32().hashUnencodedChars("http://www.google.com/"));
51     assertHash(-528633700,
52         murmur3_32().hashUnencodedChars("The quick brown fox jumps over the lazy dog"));
53   }
54 
assertHash(int expected, HashCode actual)55   private static void assertHash(int expected, HashCode actual) {
56     assertEquals(HashCode.fromInt(expected), actual);
57   }
58 
testParanoid()59   public void testParanoid() {
60     HashFn hf = new HashFn() {
61       @Override public byte[] hash(byte[] input, int seed) {
62         Hasher hasher = murmur3_32(seed).newHasher();
63         Funnels.byteArrayFunnel().funnel(input, hasher);
64         return hasher.hash().asBytes();
65       }
66     };
67     // Murmur3A, MurmurHash3 for x86, 32-bit (MurmurHash3_x86_32)
68     // http://code.google.com/p/smhasher/source/browse/trunk/main.cpp
69     HashTestUtils.verifyHashFunction(hf, 32, 0xB0F57EE3);
70   }
71 
testInvariants()72   public void testInvariants() {
73     HashTestUtils.assertInvariants(murmur3_32());
74   }
75 }
76