timezone constructor arg is case-insensitive

Use the case-insensitive match, by using the
_all_timezones_lower_to_standard map, if possible.

Signed-off-by: [ Kyle ] [ Hausmann ] <khausmann@squarespace.com>

2 files changed, 16 insertions, 1 deletions

diff --git a/src/pytz/__init__.py b/src/pytz/__init__.py
index 6208a1e..73cb991 100644
--- a/src/pytz/__init__.py
+++ b/src/pytz/__init__.py
@@ -166,7 +166,7 @@ def timezone(zone):
         # All valid timezones are ASCII
         raise UnknownTimeZoneError(zone)
 
-    zone = _unmunge_zone(zone)
+    zone = _case_insensitive_zone_lookup(_unmunge_zone(zone))
     if zone not in _tzinfo_cache:
         if zone in all_timezones_set:
             fp = open_resource(zone)
@@ -185,6 +185,11 @@ def _unmunge_zone(zone):
     return zone.replace('_plus_', '+').replace('_minus_', '-')
 
 
+def _case_insensitive_zone_lookup(zone):
+    """Get case-insensitively matching timezone, if found, else return zone unchanged"""
+    return _all_timezones_lower_to_standard.get(zone.lower()) or zone
+
+
 ZERO = datetime.timedelta(0)
 HOUR = datetime.timedelta(hours=1)
 
diff --git a/src/pytz/tests/test_tzinfo.py b/src/pytz/tests/test_tzinfo.py
index 91104cd..643f08a 100644
--- a/src/pytz/tests/test_tzinfo.py
+++ b/src/pytz/tests/test_tzinfo.py
@@ -758,6 +758,16 @@ class CommonTimezonesTestCase(unittest.TestCase):
         self.assertFalse('Europe/Belfast' in pytz.common_timezones_set)
 
 
+class ZoneCaseInsensitivityTestCase(unittest.TestCase):
+    def test_lower_case_timezone_constructor_arg(self):
+        for tz in pytz.all_timezones_set:
+            from_lower = pytz.timezone(tz.lower())
+            from_passed = pytz.timezone(tz)
+            self.assertEqual(from_lower,
+                             from_passed,
+                             "arg '{}' and arg '{}' produce different timezone objects".format(from_lower, from_passed))
+
+
 class BaseTzInfoTestCase:
     '''Ensure UTC, StaticTzInfo and DstTzInfo work consistently.