Python 3.12: do not use utcnow()

The datetime.datetime.utcnow() function is deprecated in Python 3.12,

Change-Id: I52e947e017ad1455c0310fe20fdc63354a254757

keystonemiddleware/tests/unit/auth_token/test_auth_token_middleware.py

@@ -610,7 +610,7 @@ class CommonAuthTokenMiddlewareTest(object):
         req.headers['X-Auth-Token'] = token
         req.environ.update(extra_environ)
 
-        now = datetime.datetime.utcnow()
+        now = datetime.datetime.now(datetime.timezone.utc)
         self.useFixture(TimeFixture(now))
         req.get_response(self.middleware)
         self.assertIsNotNone(self._get_cached_token(token))
@@ -1166,7 +1166,7 @@ class v3AuthTokenMiddlewareTest(BaseAuthTokenMiddlewareTest,
         data = 'this_data'
         self.set_middleware()
         self.middleware._token_cache.initialize({})
-        now = datetime.datetime.utcnow()
+        now = datetime.datetime.now(datetime.timezone.utc)
         delta = datetime.timedelta(hours=1)
         expires = strtime(at=(now + delta))
         self.middleware._token_cache.set(token, (data, expires))

keystonemiddleware/tests/unit/auth_token/test_base_middleware.py

@@ -127,7 +127,9 @@ class BaseAuthProtocolTests(testtools.TestCase):
     def test_expired_user_token(self):
         t = fixture.V3Token()
         t.set_project_scope()
-        t.expires = datetime.datetime.utcnow() - datetime.timedelta(minutes=10)
+        t.expires = (
+            datetime.datetime.now(datetime.timezone.utc)
+            - datetime.timedelta(minutes=10))
 
         token_id = uuid.uuid4().hex
         token_dict = {token_id: t}
@@ -193,7 +195,9 @@ class BaseAuthProtocolTests(testtools.TestCase):
     def test_expired_service_token(self):
         t = fixture.V3Token()
         t.set_project_scope()
-        t.expires = datetime.datetime.utcnow() - datetime.timedelta(minutes=10)
+        t.expires = (
+            datetime.datetime.now(datetime.timezone.utc)
+            - datetime.timedelta(minutes=10))
 
         token_id = uuid.uuid4().hex
         token_dict = {token_id: t}