diff --git a/tox.ini b/tox.ini
index 84b8d58d7..ea2cd1643 100644
--- a/tox.ini
+++ b/tox.ini
@@ -29,7 +29,7 @@ deps =
     pytest-html==1.3.1
 commands =
     {envpython} scripts/link_pyqt.py --tox {envdir}
-    {envpython} -m py.test --strict -rfEsw tests {posargs}
+    {envpython} -m py.test --strict -rfEsw {posargs:tests}
 
 [testenv:unittests-frozen]
 setenv = {[testenv:unittests]setenv}
@@ -52,7 +52,7 @@ deps =
     cov-core==1.15.0
 commands =
     {envpython} scripts/link_pyqt.py --tox {envdir}
-    {envpython} -m py.test --strict -rfEswx -v --cov qutebrowser --cov-report term --cov-report html tests {posargs}
+    {envpython} -m py.test --strict -rfEswx -v --cov qutebrowser --cov-report term --cov-report html {posargs:tests}
 
 [testenv:misc]
 commands =