@Test
  // 1000000 times: 733 mills.
  // 1000000 times: 770 mills.
  // 1000000 times: 746 mills.
  //
  // verified
  public void randomCalendar() {
    Calendar result = null;
    int count = 1000000;

    long beg = System.currentTimeMillis();
    for (int i = 0; i < count; i++) {
      result = CalendarHelper.randomCalendar();
    }
    long end = System.currentTimeMillis();
    System.out.println(count + " times: " + (end - beg) + " mills. ");

    System.out.println(result);
  }