Great, i’m sold 
My question regarding tests was simply because i saw on the overview at least one chapter mentioning it, and given Dave is approaching structure in a different way, i suppose it could help reasoning about it.
I took the chance and bought “Functional Web Development with Elixir, OTP, and Phoenix” book with the pragprog coupon, they seem to overlap a bit regarding the goal of separating concerns, but i haven’t really started it.
There’s a lot of quality content coming out, we truly have a rich community 
