Just install something that is NEC compliant. Sure, what you have
will work, but at what future cost? A temp install is that. Many
of us have seen temp installs that are many years old. Not all of
those encounters have good endings.

Personally, I would install an eight foot flourescent fixture with
proper wiring methods. Your temp install would be something to get
you by while performing that task (two four foot fixtures separated
by approved methods might give better lighting results).

I would guestimate the entire project would cost less than fifty bucks,
if you do it. Now, the question is, should you be the one doing it?
If not, then the under fifty guestimate goes out the door unless
you know a friend that is qualified to six-pack if for you. :-)