@Test
 public void testSetStartDate_null() {
   Date startDate = cal.getStartDate();
   cal.setStartDate(null);
   assertNotNull(cal.getStartDate());
   assertSame(startDate, cal.getStartDate());
 }
 @Test
 public void testSetStartDate() {
   Date startDate = cal.getStartDate();
   Date newStartDate = new Date();
   cal.setStartDate(newStartDate);
   assertNotNull(cal.getStartDate());
   assertNotSame(startDate, cal.getStartDate());
   assertSame(newStartDate, cal.getStartDate());
 }