diff --git a/requirements.txt b/requirements.txt
index 3d1b8d3..aca7a1f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,7 +7,7 @@ python-subunit>=0.0.18 # Apache-2.0/BSD
 six>=1.9.0 # MIT
 testrepository>=0.0.18 # Apache-2.0/BSD
 testtools>=1.4.0 # MIT
-mock>=2.0 # BSD
+mock>=2.0.0 # BSD
 mox3!=0.19.0,>=0.7.0 # Apache-2.0
 os-client-config>=1.28.0 # Apache-2.0
 debtcollector>=1.2.0 # Apache-2.0