question: set up an hour equal to hour zero , 1 january 1900 . request the previous hour , it should be null . concode_field_sep PlaceHolder placeHolder concode_field_sep void testDateConstructor1 concode_elem_sep void testGetStart concode_elem_sep void testGetLastMillisecond concode_elem_sep void testGetSerialIndex concode_elem_sep void testParseHour concode_elem_sep void testGetFirstMillisecondWithTimeZone concode_elem_sep void testNext concode_elem_sep void testGetLastMillisecondWithTimeZone concode_elem_sep void testGetFirstMillisecond concode_elem_sep void testSerialization concode_elem_sep void testDateConstructor2 concode_elem_sep void testFirstHourNext concode_elem_sep void testEqualsSelf concode_elem_sep void testLastHourNext concode_elem_sep void testGetLastMillisecondWithCalendar concode_elem_sep void testGetFirstMillisecondWithCalendar concode_elem_sep void testGetEnd concode_elem_sep void testLastHourPrevious concode_elem_sep void testHashcode concode_elem_sep void testNotCloneable concode_elem_sep void testEquals
target: void function ( ) { Hour loc0 = new Hour ( 0 , new Day ( 1 , MonthConstants . JANUARY , 1900 ) ) ; Hour loc1 = ( Hour ) loc0 . loc1 ( ) ; assertNull ( loc1 ) ; }