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
17package com.google.common.hash;
18
19import static com.google.common.hash.Hashing.murmur3_32;
20
21import com.google.common.hash.HashTestUtils.HashFn;
22
23import junit.framework.TestCase;
24
25/**
26 * Tests for {@link Murmur3_32HashFunction}.
27 */
28public class Murmur3Hash32Test extends TestCase {
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
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
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
55  private static void assertHash(int expected, HashCode actual) {
56    assertEquals(HashCode.fromInt(expected), actual);
57  }
58
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
72  public void testInvariants() {
73    HashTestUtils.assertInvariants(murmur3_32());
74  }
75}
76