Bad Starter or Starter Solenoid?

Well I really hope its not the starter, because I don't want to go through the hassle of removing the header just to get the starter out.

If I get another starter that's out of the car but still connected to the two wires should it still fire or does it need to be grounded through the transmission? I figure if I can test it not installed that would at least tell me its the starter and not the wiring. If it doesn't work either, I can always take the 2nd one back.