test for buggy < 2.6 dateutil with ambiguous tz

Author: jreback

pandas/tseries/tests/test_timezones.py

@@ -4,7 +4,7 @@
 
 import numpy as np
 import pytz
-
+from distutils.version import LooseVersion
 from pandas.types.dtypes import DatetimeTZDtype
 from pandas import (Index, Series, DataFrame, isnull, Timestamp)
 
@@ -1206,6 +1206,28 @@ def f():
         dt = Timestamp('2013-11-03 01:59:59.999999-0400', tz='US/Eastern')
         self.assertEqual(dt.tz_localize(None), dt.replace(tzinfo=None))
 
+    def test_ambiguous_compat(self):
+        # validate that pytz and dateutil are compat for dst
+        # when the transition happens
+        tm._skip_if_no_dateutil()
+        tm._skip_if_no_pytz()
+
+        result_pytz = Timestamp('2013-10-27 01:00:00').tz_localize('Europe/London', ambiguous=0)
+        result_dateutil = Timestamp('2013-10-27 01:00:00').tz_localize('dateutil//usr/share/zoneinfo/Europe/London', ambiguous=0)
+        self.assertEqual(result_pytz.value, result_dateutil.value)
+        self.assertEqual(result_pytz.value, 1382835600000000000)
+        self.assertEqual(str(result_pytz), str(result_dateutil))
+
+        # 1 hour difference
+        result_pytz = Timestamp('2013-10-27 01:00:00').tz_localize('Europe/London', ambiguous=1)
+        result_dateutil = Timestamp('2013-10-27 01:00:00').tz_localize('dateutil//usr/share/zoneinfo/Europe/London', ambiguous=1)
+        self.assertEqual(result_pytz.value, result_dateutil.value)
+        self.assertEqual(result_pytz.value, 1382832000000000000)
+
+        # dateutil < 2.6 is buggy w.r.t. ambiguous timezones
+        if dateutil.__version__ > LooseVersion('2.5.3'):
+            self.assertEqual(str(result_pytz), str(result_dateutil))
+
     def test_index_equals_with_tz(self):
         left = date_range('1/1/2011', periods=100, freq='H', tz='utc')
         right = date_range('1/1/2011', periods=100, freq='H', tz='US/Eastern')