diff --git a/tox.ini b/tox.ini
index f346c98..5fa09f8 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,6 +3,6 @@ envlist = py27,py34,py35,py36,pypy,pypy3
 
 [testenv]
 commands =
-    zope-testrunner --test-path=src
+    zope-testrunner --test-path=src []
 deps =
     .[test]