diff --git a/nixos/tests/nix-ld.nix b/nixos/tests/nix-ld.nix
index 8733f5b0c397..c62c0437e04e 100644
--- a/nixos/tests/nix-ld.nix
+++ b/nixos/tests/nix-ld.nix
@@ -13,5 +13,8 @@ import ./make-test-python.nix ({ lib, pkgs, ...} :
   testScript = ''
     start_all()
     machine.succeed("hello")
+
+    # test fallback if NIX_LD is not set
+    machine.succeed("unset NIX_LD; unset NIX_LD_LIBRARY_PATH; hello")
  '';
 })