diff --git a/tox.ini b/tox.ini
index bcfa1897..dbf32da0 100644
--- a/tox.ini
+++ b/tox.ini
@@ -23,12 +23,12 @@ commands =
 [testenv:black]
 basepython = python3.7
 commands =
-    black .
+    black {posargs} .
 
 [testenv:end-to-end]
 deps = -rtest_requirements.txt
 commands =
-    pytest tests/end-to-end
+    pytest {posargs} tests/end-to-end
 
 [testenv:isort]
 deps = {[testenv]deps}