Tests for Bug #965481

2 files changed, 38 insertions, 8 deletions

diff --git a/src/pytz/__init__.py b/src/pytz/__init__.py
index f3437ef..921eddf 100644
--- a/src/pytz/__init__.py
+++ b/src/pytz/__init__.py
@@ -199,12 +199,8 @@ HOUR = datetime.timedelta(hours=1)
 class UTC(datetime.tzinfo):
     """UTC
 
-    Identical to the reference UTC implementation given in Python docs except
-    that it unpickles using the single module global instance defined beneath
-    this class declaration.
-
-    Also contains extra attributes and methods to match other pytz tzinfo
-    instances.
+    Optimized UTC implementation. It unpickles using the single module global
+    instance defined beneath this class declaration.
     """
     zone = "UTC"
 
@@ -237,6 +233,8 @@ class UTC(datetime.tzinfo):
 
     def normalize(self, dt, is_dst=False):
         '''Correct the timezone information on the given datetime'''
+        if dt.tzinfo is self:
+            return dt
         if dt.tzinfo is None:
             raise ValueError('Naive time - no tzinfo set')
         return dt.replace(tzinfo=self)
diff --git a/src/pytz/tests/test_tzinfo.py b/src/pytz/tests/test_tzinfo.py
index 3c5d62b..92a8d57 100644
--- a/src/pytz/tests/test_tzinfo.py
+++ b/src/pytz/tests/test_tzinfo.py
@@ -725,7 +725,7 @@ class BaseTzInfoTestCase:
     These tests are run for each type of tzinfo.
     '''
     tz = None  # override
-    tzclass = None  # override
+    tz_class = None  # override
 
     def test_expectedclass(self):
         self.assertTrue(isinstance(self.tz, self.tz_class))
@@ -750,12 +750,44 @@ class BaseTzInfoTestCase:
         dt3 = new_tz.localize(dt1)
         self.assertRaises(ValueError, self.tz.fromutc, dt3)
 
+    def test_normalize(self):
+        other_tz = pytz.timezone('Europe/Paris')
+        self.assertTrue(self.tz is not other_tz)
 
-class UTCTestCase(unittest.TestCase, BaseTzInfoTestCase):
+        dt = datetime(2012, 3, 26, 12, 0)
+        other_dt = other_tz.localize(dt)
+
+        local_dt = self.tz.normalize(other_dt)
+
+        self.assertTrue(local_dt.tzinfo is not other_dt.tzinfo)
+        self.assertNotEqual(
+            local_dt.replace(tzinfo=None), other_dt.replace(tzinfo=None))
+
+    def test_astimezone(self):
+        other_tz = pytz.timezone('Europe/Paris')
+        self.assertTrue(self.tz is not other_tz)
+
+        dt = datetime(2012, 3, 26, 12, 0)
+        other_dt = other_tz.localize(dt)
+
+        local_dt = other_dt.astimezone(self.tz)
+
+        self.assertTrue(local_dt.tzinfo is not other_dt.tzinfo)
+        self.assertNotEqual(
+            local_dt.replace(tzinfo=None), other_dt.replace(tzinfo=None))
+
+
+class OptimizedUTCTestCase(unittest.TestCase, BaseTzInfoTestCase):
     tz = pytz.utc
     tz_class = tz.__class__
 
 
+class LegacyUTCTestCase(unittest.TestCase, BaseTzInfoTestCase):
+    # Deprecated timezone, but useful for comparison tests.
+    tz = pytz.timezone('Etc/UTC')
+    tz_class = StaticTzInfo
+
+
 class StaticTzInfoTestCase(unittest.TestCase, BaseTzInfoTestCase):
     tz = pytz.timezone('GMT')
     tz_class = StaticTzInfo