Adds support for external tzinfo in instance() method.

Author: sdispater

pendulum/pendulum.py

@@ -214,8 +214,13 @@ def instance(cls, dt, tz=UTC):
                 tz = tz.zone
             else:
                 # We have no sure way to figure out
-                # the timezone name, we raise an error
-                raise ValueError('Unsupported tzinfo [{}]'.format(tz))
+                # the timezone name, we fallback
+                # on a fixed offset
+                offset = dt.utcoffset()
+                if not offset:
+                    raise ValueError('Unsupported tzinfo [{}]'.format(tz))
+
+                tz = dt.utcoffset().total_seconds() / 3600
 
         return cls(
             dt.year, dt.month, dt.day,

tests/pendulum_tests/test_construct.py

@@ -3,6 +3,7 @@
 import os
 import pytz
 from datetime import datetime
+from dateutil import tz
 from pendulum import Pendulum
 from pendulum.tz import timezone
 from pendulum.tz.timezone_info import TimezoneInfo
@@ -122,6 +123,11 @@ def test_instance_timezone_aware_datetime_pytz(self):
         )
         self.assertEqual('Europe/Paris', now.timezone_name)
 
+    def test_instance_timezone_aware_datetime_any_tzinfo(self):
+        dt = datetime(2016, 8, 7, 12, 34, 56, tzinfo=tz.gettz('Europe/Paris'))
+        now = Pendulum.instance(dt)
+        self.assertEqual('+02:00', now.timezone_name)
+
     def test_now(self):
         now = Pendulum.now()
         in_paris = Pendulum.now('Europe/Paris')