diff --git a/marconi/tests/functional/base.py b/marconi/tests/functional/base.py
index d9d1ec08f..8981f73a1 100644
--- a/marconi/tests/functional/base.py
+++ b/marconi/tests/functional/base.py
@@ -18,6 +18,7 @@ import abc
 import jsonschema
 import multiprocessing
 import os
+import six
 
 from marconi.openstack.common import timeutils
 from marconi.queues import bootstrap
@@ -189,10 +190,9 @@ class FunctionalTestBase(testing.TestBase):
         self.assertTrue(0 <= delta <= 6000, msg)
 
 
+@six.add_metaclass(abc.ABCMeta)
 class Server(object):
 
-    __metaclass__ = abc.ABCMeta
-
     name = "marconi-functional-test-server"
 
     def __init__(self):