Projects like pngme

Pngme is a tutorial where besides having a spec and unit tests, there is no real hand holding for figuring out how to implement something except for links to locations in the rust docs that might be useful.

Has anyone come across similar tutorials/projects?

Edit:
I found this Rusty CS curriculum on github that has a ton of projects that seem very similar to the pngme book. I'm probably going to go through it/follow through it to see how it holds up as its currently incomplete but looks very promising: https://github.com/AbdesamedBendjeddou/Rusty-CS

I had a look at the ray tracer challenge book, and it seems language agnostic, so I'm thinking of saving that for the language that I finally settle on.