diff --git a/tox.ini b/tox.ini
index 36a8b91..804dc6c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -18,7 +18,10 @@ envlist = py38
 [testenv]
 basepython = python3.8
 deps = -rrequirements-dev.txt
-passenv = HOME SSH_AUTH_SOCK USER
+passenv =
+    HOME
+    SSH_AUTH_SOCK
+    USER
 commands =
     coverage erase
     coverage run -m pytest {posargs:tests}