1 files changed, 2 insertions, 1 deletions

diff --git a/tox.ini b/tox.ini
index 39fe024f..547d90d9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,9 +3,10 @@ envlist = py26,py27,pypy,py32,py33,docs,pep8,py3pep8
 
 [testenv]
 deps =
-    pytest
     coverage
+    iso8601
     pretend
+    pytest
 commands =
     coverage run --source=cryptography/,tests/ -m pytest --strict
     coverage report -m