@hungryjoe I think there's value in separate steps for several reasons. The primary one being semantic difference: unit testing checks semantics of the compiler output, format checking addresses the syntax of the compiler input.
The secondary is related: I want to be able to format check code that doesn't currently compile.
As a practical matter, IME format checking is faster than unit testing, so I do the former much more often. Unit testing is rarely triggered by an editor save (IME) e.g.