diff --git a/tox.ini b/tox.ini
index addf36a..3e952ac 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,6 @@
 [tox]
 envlist = py27,py34
+skipsdist = True
 [testenv]
 deps=
     pytest
@@ -8,6 +9,7 @@ deps=
     coverage
     pylint
     six
+    ecdsa
 commands=
     pep8 sshagent
     pylint --report=no --rcfile .pylintrc sshagent