void checkFormat(Job job) throws Exception {
    TaskAttemptContext attemptContext =
        new TaskAttemptContext(job.getConfiguration(), new TaskAttemptID("123", 0, false, 1, 2));

    MyClassMessagePackBase64LineInputFormat format = new MyClassMessagePackBase64LineInputFormat();
    FileInputFormat.setInputPaths(job, workDir);

    List<InputSplit> splits = format.getSplits(job);
    for (int j = 0; j < splits.size(); j++) {
      RecordReader<LongWritable, MyClassWritable> reader =
          format.createRecordReader(splits.get(j), attemptContext);
      reader.initialize(splits.get(j), attemptContext);

      int count = 0;
      try {
        while (reader.nextKeyValue()) {
          LongWritable key = reader.getCurrentKey();
          MyClassWritable val = reader.getCurrentValue();
          MyClass mc = val.get();
          assertEquals(mc.v, count);
          assertEquals(mc.s, Integer.toString(count));
          count++;
        }
      } finally {
        reader.close();
      }
    }
  }
  public void testFormat() throws Exception {
    JobConf job = new JobConf(conf);
    FileSystem fs = FileSystem.getLocal(conf);
    Path dir = new Path(System.getProperty("test.build.data", ".") + "/mapred");
    Path file = new Path(dir, "test.seq");

    Reporter reporter = Reporter.NULL;

    int seed = new Random().nextInt();
    // LOG.info("seed = "+seed);
    Random random = new Random(seed);

    fs.delete(dir, true);

    FileInputFormat.setInputPaths(job, dir);

    // for a variety of lengths
    for (int length = 0; length < MAX_LENGTH; length += random.nextInt(MAX_LENGTH / 10) + 1) {

      // LOG.info("creating; entries = " + length);

      // create a file with length entries
      SequenceFile.Writer writer =
          SequenceFile.createWriter(fs, conf, file, IntWritable.class, BytesWritable.class);
      try {
        for (int i = 0; i < length; i++) {
          IntWritable key = new IntWritable(i);
          byte[] data = new byte[random.nextInt(10)];
          random.nextBytes(data);
          BytesWritable value = new BytesWritable(data);
          writer.append(key, value);
        }
      } finally {
        writer.close();
      }

      // try splitting the file in a variety of sizes
      InputFormat<IntWritable, BytesWritable> format =
          new SequenceFileInputFormat<IntWritable, BytesWritable>();
      IntWritable key = new IntWritable();
      BytesWritable value = new BytesWritable();
      for (int i = 0; i < 3; i++) {
        int numSplits = random.nextInt(MAX_LENGTH / (SequenceFile.SYNC_INTERVAL / 20)) + 1;
        // LOG.info("splitting: requesting = " + numSplits);
        InputSplit[] splits = format.getSplits(job, numSplits);
        // LOG.info("splitting: got =        " + splits.length);

        // check each split
        BitSet bits = new BitSet(length);
        for (int j = 0; j < splits.length; j++) {
          RecordReader<IntWritable, BytesWritable> reader =
              format.getRecordReader(splits[j], job, reporter);
          try {
            int count = 0;
            while (reader.next(key, value)) {
              // if (bits.get(key.get())) {
              // LOG.info("splits["+j+"]="+splits[j]+" : " +
              // key.get());
              // LOG.info("@"+reader.getPos());
              // }
              assertFalse("Key in multiple partitions.", bits.get(key.get()));
              bits.set(key.get());
              count++;
            }
            // LOG.info("splits["+j+"]="+splits[j]+" count=" +
            // count);
          } finally {
            reader.close();
          }
        }
        assertEquals("Some keys in no partition.", length, bits.cardinality());
      }
    }
  }