@Test
  public void testJobConfigurationsWithDryMode() throws Exception {
    Path bulkOutputPath = new Path(util.getDataTestDirOnTestFS(tn.getNameAsString()), "hfiles");
    String INPUT_FILE = "InputFile1.csv";
    // Prepare the arguments required for the test.
    String[] argsArray =
      new String[] { "-D" + ImportTsv.COLUMNS_CONF_KEY + "=HBASE_ROW_KEY,FAM:A,FAM:B",
        "-D" + ImportTsv.SEPARATOR_CONF_KEY + "=,",
        "-D" + ImportTsv.BULK_OUTPUT_CONF_KEY + "=" + bulkOutputPath.toString(),
        "-D" + ImportTsv.DRY_RUN_CONF_KEY + "=true", tn.getNameAsString(), INPUT_FILE };
    assertEquals("running test job configuration failed.", 0,
      ToolRunner.run(new Configuration(util.getConfiguration()), new ImportTsv() {
        @Override
        public int run(String[] args) throws Exception {
          Job job = createSubmittableJob(getConf(), args);
          assertTrue(job.getOutputFormatClass().equals(NullOutputFormat.class));
          return 0;
        }
      }, argsArray));
    // Delete table created by createSubmittableJob.
    util.deleteTable(tn);
  }
Force use of combiner in doMROnTableTest. Boolean. Default is true.
hbase-mapreduce/src/test/java/org/apache/hadoop/hbase/mapreduce/TestImportTsv.java