Depends on what your going to do with it .. I have owned several tractors and for just around the house I would never buy less than a 30 hp with a loader .
TSC has a little light tester for around 5 bucks , when my daughter was little I paid her a quarter to test it for me after a while she got use to it and was no problem and do it for fun and grab other people ,, lol
try switching it in and out while taping it sometimes they stick if it works just remember to kick it in about once a week ,,,be careful and un over anyone do it in neutral
Test isn't that bad ,, Remember that they are different classification and make sure you take what you need ,, here is the only hard part you must do a hands on inspection and without proper knowledge and hands on experience with a truck your wasting your time books want teach you that . you...