Fix for launchpad #267545: DateTime(DateTime()) should preserve the correct hour

doc/CHANGES.txt

@@ -207,6 +207,9 @@ Zope Changes
 
     Bugs Fixed
 
+      - Launchpad #267545: DateTime(DateTime()) now preserves the
+        correct hour
+
       - Launchpad #262313: respect the 'Expand macros when editing' flag
         when editing a page template through the ZMI
 

lib/python/DateTime/DateTime.py

@@ -586,11 +586,8 @@ class DateTime:
                 DateTime instance.
                 """
                 t = arg.timeTime()
-                tz = arg.timezone()
-                ms = (t - math.floor(t))
                 s,d = _calcSD(t)
-                yr,mo,dy,hr,mn,sc = gmtime(t)[:6]
-                sc = sc + ms
+                yr,mo,dy,hr,mn,sc,tz = arg.parts()
             
             elif isinstance(arg, datetime):
                 yr,mo,dy,hr,mn,sc,numerictz,tznaive=self._parse_iso8601_preserving_tznaive(arg.isoformat())

lib/python/DateTime/tests/testDateTime.py

@@ -401,8 +401,10 @@ class DateTimeTests(unittest.TestCase):
     def testCopyConstructor(self):
         d = DateTime('2004/04/04')
         self.assertEqual(DateTime(d), d)
-        d = DateTime('1999/04/12')
-        self.assertEqual(DateTime(d), d)
+        self.assertEqual(str(DateTime(d)), str(d))
+        d2 = DateTime('1999/04/12 01:00:00')
+        self.assertEqual(DateTime(d2), d2)
+        self.assertEqual(str(DateTime(d2)), str(d2))
 
     def testCopyConstructorPreservesTimezone(self):
         # test for https://bugs.launchpad.net/zope2/+bug/200007
@@ -413,8 +415,10 @@ class DateTimeTests(unittest.TestCase):
         self.assertEqual(DateTime(d).timezone(), d.timezone())
         d2 = DateTime('2008/04/25 12:00:00 EST')
         self.assertEqual(DateTime(d2).timezone(), d2.timezone())
+        self.assertEqual(str(DateTime(d2)), str(d2))
         d3 = DateTime('2008/04/25 12:00:00 PST')
         self.assertEqual(DateTime(d3).timezone(), d3.timezone())
+        self.assertEqual(str(DateTime(d3)), str(d3))
 
 
     def testRFC822(self):