The sole purpose of which, is to make sure alternative ad and macros files supplied to us by clients work.
Use the context "ad-test" and the DFP campaign "ad-test".
Hopefully, whatever the client has given you will be roadblocked here and you can move on with your day.
If not, then sucks to be you because it means you've got to go back to the client and ask for new files. Good luck with that.