AdMob in Editor?

Trying to set up AdMob for use in iOS/Android games, but I’d also like to see the ads stubbed in the editor. I’m following this guide: 1, and obviously it isn’t showing up in the editor. I’m totally clueless how to set this up but I’d like to be able to see what screen space is taken up by the ads while building my games. Any tips?

*Using Unity 5

Okay simply AdMob can be shown on 2 platforms Android/IOS, but you can make an ad simulator!
just make an image with the same ad size.

AdSize youradSize = AdSize.Banner;
yourImageObject.GetComponent<RectTransform>().sizeDelta = new Vector2(youradSize.Width, youradSize.Height);

so you will avoid design problems!