Unconditionally use PyPI mock

test/test_functional.py

@@ -2,17 +2,13 @@ import os
 import json
 
 import six
+import mock
 
 from ddt import ddt, data, file_data
 from nose.tools import assert_equal, assert_is_not_none, assert_raises
 
 from test.mycode import has_three_elements
 
-try:
-    from unittest import mock
-except ImportError:
-    import mock
-
 
 @ddt
 class Dummy(object):