code: public void testVaryingNumberOfDailyPeriods(){
    RollingCalendar rc=new RollingCalendar();
    rc.init("yyyy-MM-dd");
    final long MILLIS_IN_DAY=24 * 3600 * 1000;
    for (int p=20; p > -100; p--) {
      long now=1223325293589L;
      Date nowDate=new Date(now);
      Date result=rc.getRelativeDate(nowDate,p);
      long offset=rc.getTimeZone().getRawOffset() + rc.getTimeZone().getDSTSavings();
      long origin=now - (now % (MILLIS_IN_DAY)) - offset;
      long expected=origin + p * MILLIS_IN_DAY;
      assertEquals("p=" + p,expected,result.getTime());
    }
  }
  