diff --git a/tox.ini b/tox.ini
index fdac2b330..2ee9cdbc1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -17,6 +17,7 @@ commands = flake8
 
 [testenv:functional]
 setenv = OS_TEST_PATH=./functional/tests
+passenv = OS_*
 
 [testenv:venv]
 commands = {posargs}