diff --git a/tox.ini b/tox.ini
index 01bb819ca..ef5f773df 100644
--- a/tox.ini
+++ b/tox.ini
@@ -18,7 +18,7 @@ setenv =
     PYTHONDONTWRITEBYTECODE=1
     TZ=UTC
     TESTS_DIR=./ironic_inspector/test/unit/
-passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
+passenv = http_proxy,HTTP_PROXY,https_proxy,HTTPS_PROXY,no_proxy,NO_PROXY
 
 [testenv:venv]
 commands = {posargs}