I built an ebike throttle and brake tester

5v meanwell
panel voltmeter from ebay
speak spring terminals from ebay

EZ PZ. Brakes go from 0v-5v on-off
Throttles go from 0v-5v in a sweep
(oddly the off position with throttles has been between .6v and .9v - i didn't realize that was the case)

I built this rig to test the 100 lbs of throttles and brake levers i have sitting in my workroom.

Most of us have this one in the tool kit. 9$ on Ebay