code: private long getDuration(Set<ITestResult> results)
      {
          long duration = 0;
          for (ITestResult result : results)
          {
              duration += (result.getEndMillis() - result.getStartMillis());
          }
          return duration;
      }
docs: Returns the aggregate of the elapsed times for each test result.
  @param results A set of test results.
  @return The sum of the test durations.