public int hash(byte[] bytes) {
    return hash(bytes, bytes.length, -1);
  }
@Test
  public void testHash() {
    int iterations = 30;
    assertTrue("testHash jenkins error !!!",
        Hash.JENKINS_HASH == Hash.parseHashType("jenkins"));
    assertTrue("testHash murmur error !!!",
        Hash.MURMUR_HASH == Hash.parseHashType("murmur"));
    assertTrue("testHash undefined",
        Hash.INVALID_HASH == Hash.parseHashType("undefined"));

    Configuration cfg = new Configuration();
    cfg.set("hadoop.util.hash.type", "murmur");
    assertTrue("testHash", MurmurHash.getInstance() == Hash.getInstance(cfg));

    cfg = new Configuration();
    cfg.set("hadoop.util.hash.type", "jenkins");
    assertTrue("testHash jenkins configuration error !!!",
        JenkinsHash.getInstance() == Hash.getInstance(cfg));

    cfg = new Configuration();
    assertTrue("testHash undefine configuration error !!!",
        MurmurHash.getInstance() == Hash.getInstance(cfg));

    assertTrue("testHash error jenkin getInstance !!!",
        JenkinsHash.getInstance() == Hash.getInstance(Hash.JENKINS_HASH));
    assertTrue("testHash error murmur getInstance !!!",
        MurmurHash.getInstance() == Hash.getInstance(Hash.MURMUR_HASH));

    assertNull("testHash error invalid getInstance !!!",
        Hash.getInstance(Hash.INVALID_HASH));

    int murmurHash = Hash.getInstance(Hash.MURMUR_HASH).hash(LINE.getBytes());
    for (int i = 0; i < iterations; i++) {
      assertTrue("multiple evaluation murmur hash error !!!",
          murmurHash == Hash.getInstance(Hash.MURMUR_HASH)
              .hash(LINE.getBytes()));
    }

    murmurHash = Hash.getInstance(Hash.MURMUR_HASH).hash(LINE.getBytes(), 67);
    for (int i = 0; i < iterations; i++) {
      assertTrue(
          "multiple evaluation murmur hash error !!!",
          murmurHash == Hash.getInstance(Hash.MURMUR_HASH).hash(
              LINE.getBytes(), 67));
    }

    int jenkinsHash = Hash.getInstance(Hash.JENKINS_HASH).hash(LINE.getBytes());
    for (int i = 0; i < iterations; i++) {
      assertTrue(
          "multiple evaluation jenkins hash error !!!",
          jenkinsHash == Hash.getInstance(Hash.JENKINS_HASH).hash(
              LINE.getBytes()));
    }

    jenkinsHash = Hash.getInstance(Hash.JENKINS_HASH).hash(LINE.getBytes(), 67);
    for (int i = 0; i < iterations; i++) {
      assertTrue(
          "multiple evaluation jenkins hash error !!!",
          jenkinsHash == Hash.getInstance(Hash.JENKINS_HASH).hash(
              LINE.getBytes(), 67));
    }   
  }