--- contrib/python/requests-mock/py3/tests/base.py	(index)
+++ contrib/python/requests-mock/py3/tests/base.py	(working tree)
@@ -10,8 +10,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-import testtools
+import unittest
 
 
-class TestCase(testtools.TestCase):
+class TestCase(unittest.TestCase):
     pass