Caution, make sure all bare wires are taped off and not cross connected to each other before attempting the following:
Presuming no electrical hook up meaning the ignition switch connections and T&T wiring not connected, you can still check all three, i.e. spark, starter and compression. You will need remote starter which is basically nothing but a two pole (On/Off) switch and of course a battery. For the battery, if there are no large red and black cables on the motor (for battery connection, if there are battery cables then connect them to the battery), you can just use jumper cables. Connect the positive to the solenoid main terminal and the black to ground. Connect the remote starter across the solenoid coil terminals (two small terminals). Remove all spark plugs and ground the plug wires and insert/thread in a compression gauge. By simply pushing down the remote starter the starter should engage and crank over the motor to give you compression readings.
If you do not have a remote starter, you can still check starter and compression by directly jumping the starter, positive to the starter terminal and black/negative to ground. This will activate the starter and hopefully crank over the motor to get compression readings.
You can also do simultaneously the spark test. If the shut down wire (white wire from the engine terminal board) is disconnected (just make sure it is not touching ground or better yet tape it off), which it should since there's no ignition switch wired, you should also see sparks from the plugs if you have a spark tester connected to the plug wires.
Since there's no fuel connection you might want to bring in a oiler of some kind to oil the cylinders through the plug holes before cranking it over. Even spray can fogging oil will do.
