### Question:
AutoInputFormat extends FileInputFormat { public RecordReader getRecordReader(InputSplit split, JobConf job, Reporter reporter) throws IOException { FileSplit fileSplit = (FileSplit) split; FileSystem fs = FileSystem.get(fileSplit.getPath().toUri(), job); FSDataInputStream is = fs.open(fileSplit.getPath()); byte[] header = new byte[3]; RecordReader reader = null; try { is.readFully(header); } catch (EOFException eof) { reader = textInputFormat.getRecordReader(split, job, reporter); } finally { is.close(); } if (header[0] == 'S' && header[1] == 'E' && header[2] == 'Q') { reader = seqFileInputFormat.getRecordReader(split, job, reporter); } else { reader = textInputFormat.getRecordReader(split, job, reporter); } return reader; }  void configure(JobConf job); RecordReader getRecordReader(InputSplit split, JobConf job,
    Reporter reporter);  }### Answer:
@SuppressWarnings( { "unchecked", "deprecation" }) @Test public void testFormat() throws IOException { JobConf job = new JobConf(conf); FileSystem fs = FileSystem.getLocal(conf); Path dir = new Path(System.getProperty("test.build.data", ".") + "/mapred"); Path txtFile = new Path(dir, "auto.txt"); Path seqFile = new Path(dir, "auto.seq"); fs.delete(dir, true); FileInputFormat.setInputPaths(job, dir); Writer txtWriter = new OutputStreamWriter(fs.create(txtFile)); try { for (int i = 0; i < LINES_COUNT; i++) { txtWriter.write("" + (10 * i)); txtWriter.write("\n"); } } finally { txtWriter.close(); } SequenceFile.Writer seqWriter = SequenceFile.createWriter(fs, conf, seqFile, IntWritable.class, LongWritable.class); try { for (int i = 0; i < RECORDS_COUNT; i++) { IntWritable key = new IntWritable(11 * i); LongWritable value = new LongWritable(12 * i); seqWriter.append(key, value); } } finally { seqWriter.close(); } AutoInputFormat format = new AutoInputFormat(); InputSplit[] splits = format.getSplits(job, SPLITS_COUNT); for (InputSplit split : splits) { RecordReader reader = format.getRecordReader(split, job, Reporter.NULL); Object key = reader.createKey(); Object value = reader.createValue(); try { while (reader.next(key, value)) { if (key instanceof LongWritable) { assertEquals("Wrong value class.", Text.class, value.getClass()); assertTrue("Invalid value", Integer.parseInt(((Text) value) .toString()) % 10 == 0); } else { assertEquals("Wrong key class.", IntWritable.class, key.getClass()); assertEquals("Wrong value class.", LongWritable.class, value .getClass()); assertTrue("Invalid key.", ((IntWritable) key).get() % 11 == 0); assertTrue("Invalid value.", ((LongWritable) value).get() % 12 == 0); } } } finally { reader.close(); } } }