How to test spark plug?

[Smith]

I took out the spark plug from the piston on my weed eater and kept it in the plug cap and pulled to see if i had spark, i was holding the rubber but it shocked me.

I think there might be a problem with the spark plug cap, so i have no way to test my plug. Does anyone know how i could test the plug besides the way i just did it?

[HCT]

take out the spark plug, connect the spark plug cable to it then connect a ground to the spark plug and start the weed eater to see if the spark plug creates a spark