diff --git a/tox.ini b/tox.ini
index da64de71..43528d0c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -13,5 +13,5 @@ deps =
   optional: -r{toxinidir}/requirements-optional.txt
 
 commands =
-  {envbindir}/py.test
+  {envbindir}/py.test {posargs}
   {toxinidir}/flake8-run.sh