There are only four ways to test an electric fence worth mentioning:
1) Use an electric fence tester. Available from any good electrical fence retailer, for around 12 of your Earth euros. (Pain level: Slight, and confined to the wallet.)
2) Use a long blade of grass. Squat down and rest one hand on the ground and touch the electric fence with the blade of grass. (Pain level: A bit of a shock, even with the fence turned down low.)
3) Use someone else. (Pain level: Like watching something written by Ricky Gervais.)
4) Use your knee. Wearing wellies, gently touch your knee against the fence - turned up to maximum - and earth yourself through the middle finger of your left hand, with a fencing staple brushing against a roll of barbed wire. (Pain level: Hilarious.)
No prizes for guessing which method I used this morning.