Does riot actually play test new champs?

Theres no way riot actually play tested zoe and thought it was a good idea to put her in the game in the state she is. Like being abled to stun someone for 2 seconds while having an ability able to one shot a squishy while behind is so unbalanced. Maybe for professionals where they can play near perfect she isnt that bad but for most of the community we will make mistakes and when you hav to vs zoe you have to play near perfect if not perfect to win and if you dont you just feed. With her poke you can hit people without them even knowing where it is coming from. I recently vs a zoe top where she would just hide in bushes and i couldnt even predict where they were coming from. I would ward but its hard when she buys scanners and control wards making it impossible to stop her. Well anyway what do you guys think riot seems to alway make overpowered champs on release and then tone them down which i feel is from their lack of play testing.