Practice Mode?

In the mobile MOBA, Vainglory, there is a mode where every champion/hero is available. It is solo practice. you are alone on the The Halcyon Fold, (Vainglory's Summoner's Rift), and you can practice building, farming , etc. All without other players there. I was wondering if such a mode would be added to LoL, as it would be a helpful way to review a champion before you spend money or IP on it. I have found this useful in Vainglory and I think it would be a benefit in LoL.