Testing a champoion

I think that there should be a way to test a champion and there abilities before u actually buy them. If you plan on buying someone really expensive that looks really cool but you've never played him, you should be able to test him out. Only in like a bot match or a custom match for a limited time. Because I watched all these montages and thought that Gnar looked really cool. So i saved up for him and when i bought him, i ended up not liking him at all and never used him. I bet people do that a lot. Just something that was on my mind and for riot to really consider. Anyone agree? Disagree? comment! -AlexMitchell444