add container test driver

checks/lib/container-driver/test-script-prepend.py

@@ -0,0 +1,9 @@
+# This file contains type hints that can be prepended to Nix test scripts so they can be type
+# checked.
+
+from typing import Callable, List
+
+from test_driver import Machine
+
+start_all: Callable[[], None]
+machines: List[Machine]