OK, what you do not want to do is try to get a long length spark out of the ignition system. As that quickly causes the windings inside the ignition coil to go bad. But many ignition systems use a metal spark plug cap and it makes contact with the spark plug case and also the shielded braid wire on the spark plug wire. They also may have a small coil spring in the spark plug cap to also grab and hold the spark plug cap onto the spark plug too. Thus the return path or ground is through the spark plug wire.
So you should be able to pull the spark plug and plug it into the spark plug cap and with the ignition system powered up, rotate the propeller to see a spark on the spark plug. It is a small spark so doing it with less light and in the shade is needed. You can also just rotate the crankshaft so the magnet passes by the sensor too.

Now if you have a ignition system that uses a unshielded spark plug wire, then you need to ensure the spark plug body is grounded when you go to check for a spark.