diff --git a/tox.ini b/tox.ini
index 5d39f6ed..cb0db4b0 100644
--- a/tox.ini
+++ b/tox.ini
@@ -23,7 +23,9 @@ deps =
 
 allowlist_externals =
   make
-passenv = *_proxy *_PROXY
+passenv =
+  *_proxy
+  *_PROXY
 
 [testenv:package]
 commands =