datetimetester.py 文件源码

def test_bogus_dst(self):
        class ok(tzinfo):
            def utcoffset(self, dt): return HOUR
            def dst(self, dt): return HOUR

        now = self.theclass.now().replace(tzinfo=utc_real)
        # Doesn't blow up.
        now.astimezone(ok())

        # Does blow up.
        class notok(ok):
            def dst(self, dt): return None
        self.assertRaises(ValueError, now.astimezone, notok())

        # Sometimes blow up. In the following, tzinfo.dst()
        # implementation may return None or not None depending on
        # whether DST is assumed to be in effect.  In this situation,
        # a ValueError should be raised by astimezone().
        class tricky_notok(ok):
            def dst(self, dt):
                if dt.year == 2000:
                    return None
                else:
                    return 10*HOUR
        dt = self.theclass(2001, 1, 1).replace(tzinfo=utc_real)
        self.assertRaises(ValueError, dt.astimezone, tricky_notok())