code: public void run(List<Record> input, List<Record> output) {
          if (input.size() < 0) {
              fail("input size is 0");
          }
          driver.setConfiguration(conf);
  
          Key key = input.get(0).getKey();
          boolean groupingNothing = input.get(0).isGroupingNothing();
  
          List<Writable> values = new ArrayList<Writable>();
          for (Record record : input) {
              values.add(record.isValueNothing() ? NullWritable.get() : record.getValue());
          }
  
          driver.withInput(groupingNothing ? NullWritable.get() : key,
                           values);
  
          if (output != null) {
              for (Record r : output) {
                  driver.withOutput(r.isGroupingNothing() ? NullWritable.get() : r.getKey(),
                                    r.isValueNothing() ? NullWritable.get() : r.getValue());
              }
          }
  
          driver.runTest();
      }
docs: Run the test with this method.
  @param input input {@link Record} {@link List}
  @param output result of {@link Record} {@link List}