diff --git a/tox.ini b/tox.ini
index a6fe96f..936e0d9 100644
--- a/tox.ini
+++ b/tox.ini
@@ -8,7 +8,8 @@ install_command = pip install {opts} {packages}
 passenv =
     HOME
     TERM
-    SNAP_BUILD_PROXY
+    SNAPSTACK_HTTP_PROXY
+    SNAPSTACK_HTTPS_PROXY
 whitelist_externals =
     sudo
     snapcraft