How do I determine that the electronics are working with the test firmware?
Running this kind of test isn't really necessary; it provides a nice test to see if everything is working but so does uploading actual firmware (and this isn't any safer than traditional firmware, at that).

It looks like it runs the steppers in one direction for 5 seconds and then in reverse for 5, which should be more than enough to see them move even with 1/32 stepping (it moves them at 1 step/ms, which would come out to 3/4ths of a turn with 1/200 steppers and 1/32 microstepping).

It isn't necessary to remove any code that isn't used. It does no harm.