@Override
  protected int doWork() throws Exception {
    // this is called from the command line, so we should set to use the distributed cluster
    IntegrationTestingUtility.setUseDistributedCluster(conf);
    Class<?>[] classes = findIntegrationTestClasses();
    LOG.info("Found " + classes.length + " integration tests to run:");
    for (Class<?> aClass : classes) {
      LOG.info("  " + aClass);
    }
    JUnitCore junit = new JUnitCore();
    junit.addListener(new TextListener(System.out));
    Result result = junit.run(classes);

    return result.wasSuccessful() ? 0 : 1;
  }
Returns test classes annotated with @Category(IntegrationTests.class), according to the filter
specific on the command line (if any).
hbase-it/src/test/java/org/apache/hadoop/hbase/IntegrationTestsDriver.java