diff --git a/tox.ini b/tox.ini
index 9014d59..99a92f2 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,6 +13,7 @@
 install_command = pip install -U {opts} {packages}
 deps =
     -r{toxinidir}/tcp_tests/requirements.txt
+    mock>=1.2
 usedevelop = False
 commands = py.test -s -vvv tcp_tests/tests/unit