/** * Copyright 2005 The Apache Software Foundation * * 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 org.apache.hadoop.io;import org.apache.hadoop.io.TestWritable;import junit.framework.TestCase;import java.security.MessageDigest;import java.util.Random;/** Unit tests for MD5Hash. */public class TestMD5Hash extends TestCase {  public TestMD5Hash(String name) { super(name); }  private static final Random RANDOM = new Random();  public static MD5Hash getTestHash() throws Exception {    MessageDigest digest = MessageDigest.getInstance("MD5");    byte[] buffer = new byte[1024];    RANDOM.nextBytes(buffer);    digest.update(buffer);    return new MD5Hash(digest.digest());  }  public void testMD5Hash() throws Exception {    MD5Hash md5Hash = getTestHash();    MD5Hash md5Hash00      = new MD5Hash(new byte[] {0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0});    MD5Hash md5HashFF      = new MD5Hash(new byte[] {-1,-1,-1,-1,-1,-1,-1,-1,                                -1,-1,-1,-1,-1,-1,-1,-1});    // test i/o    TestWritable.testWritable(md5Hash);    TestWritable.testWritable(md5Hash00);    TestWritable.testWritable(md5HashFF);    // test equals()    assertEquals(md5Hash, md5Hash);    assertEquals(md5Hash00, md5Hash00);    assertEquals(md5HashFF, md5HashFF);    // test compareTo()    assertTrue(md5Hash.compareTo(md5Hash) == 0);    assertTrue(md5Hash00.compareTo(md5Hash) < 0);    assertTrue(md5HashFF.compareTo(md5Hash) > 0);    // test toString and string ctor    assertEquals(md5Hash, new MD5Hash(md5Hash.toString()));    assertEquals(md5Hash00, new MD5Hash(md5Hash00.toString()));    assertEquals(md5HashFF, new MD5Hash(md5HashFF.toString()));  }	}