possibly a flashlight battery/flashlight bulb & several jumper wires with alligator clips. Likely you could take the top of a flashlight & jump from the center terminal of the top battery & the copper "slide" on the side that comes up from the lower battery negative bottom (whichever way is easiest for you with what you have). it wouldn't be near the same voltage but if it does show continuity then you know that that is the problem.