diff --git a/lib/test/container-test-driver/test_driver/__init__.py b/lib/test/container-test-driver/test_driver/__init__.py
index b17af3a8c..197783a55 100644
--- a/lib/test/container-test-driver/test_driver/__init__.py
+++ b/lib/test/container-test-driver/test_driver/__init__.py
@@ -150,7 +150,7 @@ class Error(Exception):
     pass
 
 
-def prepare_machine_root(machinename: str, root: Path) -> None:
+def prepare_machine_root(root: Path) -> None:
     root.mkdir(parents=True, exist_ok=True)
     root.joinpath("etc").mkdir(parents=True, exist_ok=True)
     root.joinpath(".env").write_text(
@@ -197,7 +197,7 @@ class Machine:
         return self.get_systemd_process()
 
     def start(self) -> None:
-        prepare_machine_root(self.name, self.rootdir)
+        prepare_machine_root(self.rootdir)
         init_test_environment()
         cmd = [
             "systemd-nspawn",