How do I write unit tests to make sure my date/time based code works for all time zones and with/out DST?

Question

I\'m using JodaTime 2.1 and I\'m looking for a pattern to unit test code which performs date/time operations to make sure it behaves well for all time zones and independent

Answer 1

for (String zoneId : DateTimeZone.getAvailableIDs())
{
   DateTime testedDate1;
   DateTime testedDate2;
   try
   {
      final DateTimeZone tz = DateTimeZone.forID(zoneId);
      // your test with testedDate1 and testedDate2 
   }
   catch (final IllegalArgumentException e)
   {
      // catching DST problem
      testedDate1 = testetDate1.plusHours(1);
      testedDate2 = testetDate2.plusHours(1);
      // repeat your test for this dates
   }
}

Change for single test

DateTimeZone default;  

DateTimeZone testedTZ;

@Before
public void setUp()
{
   default = GateTimeZone.getDefault();
   DateTimeZone.setDefault
}  

@After
public void tearDown()
{
   default = GateTimeZone.setDefault();
   DateTimeZone.setDefault(testedTZ)
}   

@Test
public void test()
{
//...
}