diff --git a/keystonemiddleware/auth_token/_cache.py b/keystonemiddleware/auth_token/_cache.py
index d40f5842..cef6cc19 100644
--- a/keystonemiddleware/auth_token/_cache.py
+++ b/keystonemiddleware/auth_token/_cache.py
@@ -268,6 +268,8 @@ class TokenCache(object):
         if serialized is None:
             return None
 
+        if isinstance(serialized, six.text_type):
+            serialized = serialized.encode('utf8')
         data = self._deserialize(serialized, context)
 
         # Note that _INVALID_INDICATOR and (data, expires) are the only
diff --git a/keystonemiddleware/tests/unit/utils.py b/keystonemiddleware/tests/unit/utils.py
index da6f347a..5aaaeb46 100644
--- a/keystonemiddleware/tests/unit/utils.py
+++ b/keystonemiddleware/tests/unit/utils.py
@@ -108,7 +108,7 @@ class DisableModuleFixture(fixtures.Fixture):
 
     def clear_module(self):
         cleared_modules = {}
-        for fullname in sys.modules.keys():
+        for fullname in list(sys.modules.keys()):
             if (fullname == self.module or
                     fullname.startswith(self.module + '.')):
                 cleared_modules[fullname] = sys.modules.pop(fullname)