driver.withOutputFormat(TextOutputFormat.class, TextInputFormat.class);
driver.withInputKey(new Text("a"));
driver.withInputValue(new LongWritable(1)).withInputValue(
new LongWritable(2));
driver.withOutput(new LongWritable(), new Text("a\t3"));
driver.runTest();
}
@Test
public void testRepeatRun() throws IOException {
final List<LongWritable> vals = new ArrayList<LongWritable>();