Fixes timezone_() not setting the tzinfo properly.

Author: sdispater

pendulum/pendulum.py

@@ -17,7 +17,6 @@
 from .tz import Timezone, UTC, FixedTimezone, local_timezone
 from .tz.timezone_info import TimezoneInfo
 from .formatting import FORMATTERS
-from ._compat import basestring
 from .constants import (
     SUNDAY, MONDAY, TUESDAY, WEDNESDAY,
     THURSDAY, FRIDAY, SATURDAY,
@@ -500,12 +499,11 @@ def _setter(self, **kwargs):
         return self._tz.convert(self.replace(**kwargs))
 
     def timezone_(self, tz):
-        tz = self._safe_create_datetime_zone(tz)
-
-        dt = self.copy()
-        dt._tz = tz
-
-        return dt
+        return self.__class__(
+            self.year, self.month, self.day,
+            self.hour, self.minute, self.second, self.microsecond,
+            tz
+        )
 
     def tz_(self, tz):
         return self.timezone_(tz)

tests/pendulum_tests/test_fluent_setters.py

@@ -61,6 +61,7 @@ def test_fluid_timezone_setter(self):
         new = d.timezone_('Europe/Paris')
         self.assertIsInstanceOfPendulum(new)
         self.assertEqual('Europe/Paris', new.timezone_name)
+        self.assertEqual('Europe/Paris', new.tzinfo.tz.name)
 
     def test_fluid_tz_setter(self):
         d = Pendulum.create(2016, 7, 2, 0, 41, 20)