> If you would like to modernise your font-lock test, I would be happy to contribute it to Emacs (as I suggested in
> bug#16063).

Why wouldn't we want that? Please go ahead, and thanks.

Thanks! In which branch should I add it, master or Emacs-26?

I guess it should go into lisp/emacs-lisp, as "ert.el" is located there.

-- Anders