diff --git a/test-requirements.txt b/test-requirements.txt
index c22f516..3a10a63 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -15,7 +15,7 @@ python-subunit>=0.0.18
 sphinx>=1.1.2,<1.2
 sphinxcontrib_issuetracker
 testrepository>=0.0.17
-testtools>=0.9.34
+testtools>=0.9.34,<0.9.36
 
 scripttest
 # NOTE(rpodolyaka): This version identifier is currently necessary as