diff --git a/tox.ini b/tox.ini
index dda4b08..d9e1768 100644
--- a/tox.ini
+++ b/tox.ini
@@ -11,6 +11,9 @@ install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstac
 deps = -r{toxinidir}/test-requirements.txt
 commands =
 
+[testenv:venv]
+commands = {posargs}
+
 [testenv:docs]
 deps = -r{toxinidir}/doc/requirements.txt
 commands =