Q: How can I tell if I have a bad neutral safety switch?

I have this 2002 Ford Explorer that has way over 200,000 miles on it. I drove it to the hardware store went in for about five minutes got back in and turn the key and nothing. The lights, horn, wiper, dash, and dome lights works fine. So I had to call AAA and get them to pick it up then the first thing i done was get my vote meters and check the battery and it was 11.7 so I figure that was about right because I was checking the lights and stuff then I went to the positive cable at the starter and had power there then I checked the small wire that went to the starter and had my son turn the key but there was no power so i took the starter off and bench tested it and it woke right up so I said it must be the neutral safety switch. So my question is how do you test the switch. This vehicle is a spare that I keep just in case we need it and it gets about 500 miles a year on it.

My car has 20000 miles.
My car has an automatic transmission.