In my company, the stick pusher is not checked explicitly; just the Push off -PB is checked to be not latched in in each preflight and before the first flight of the day, a Stall warning system test is executed.
Wired backwards - in a sense that the stick pusher works as stick puller in the case of a stall? Rather unlikely. In case both Stall protection modules agree, the stick pusher is triggered electrically, but the actuation is by hydraulics.