diff --git a/nixos/tests/make-test-python.nix b/nixos/tests/make-test-python.nix
index 32531fffd2bf..28569f1d2955 100644
--- a/nixos/tests/make-test-python.nix
+++ b/nixos/tests/make-test-python.nix
@@ -1,5 +1,5 @@
 f: {
-  system,
+  system ? builtins.currentSystem,
   pkgs ? import ../.. { inherit system; config = {}; overlays = []; },
   ...
 } @ args: