For now, we note that programming a computer to pass a rigorously applied test provides plenty to work on.
Does "plenty to work on" here mean there is a lot of things to be done?
You are quite close, and would be correct in most usage.
Plenty to work on
(in this case) does not mean that there are a lot of things to be done,
just that the single task mentioned ('programming a computer') will require lots of effort and/or thought.