I don't know (and don't care) if this makes your unit tests faster, you shouldn't write code like that. He took something that should be simple and made it really complicated. The execution time of your tests shouldn't dictate how you will design and write your application. Especially if it makes things harder to maintain and understand.

Edit: I love tests and they should be fast so that you can run them every time before pushing your changes but as I said they shouldn't dictate how you design and write your application.