The simple inexpensive tool for that is a sturdy screwdriver. If you try to use a remote starter clipped to the two main terminals of the starter solenoid you will burn it up an a flash. There is over 100+ amps of current in that circuit and it will burn up any wire smaller than the battery cable that feeds it. Therefore. you bridge those two terminals with a sturdy screwdriver. That's the basic starter test.
If you bridge the large battery side terminal to the terminal for the small red/blue wire, again a screwdriver is the simplest and most effective tool to use. There is less than 5 amps of current flowing through that circuit.