(* OS.Path.joinDirFile should raise InvalidArc if the file name does not correspond to an arc *)
(OS.Path.joinDirFile {dir="abc/def", file="ghi/jkl"}; raise Fail "incorrect") handle OS.Path.InvalidArc => ();

Add a test to check that OS.Path.joinDirFile correctly checks file-name
Add a test to check that OS.Path.joinDirFile correctly checks file-name
