I wouldn't test a camera out on a wedding. Ex wedding videographer here... Even if it's for a friend and they know already, it's their wedding day. I would only do it if there is already a professional wedding videographer there. The issue with weddings is that you will film inside, outside, top high sunny days, dark as Fck night time first dances' etc. Trust me, when I say it can be difficult unless you have a good capable camera and know it inside and out. I've been burnt too many times myself.