[thraxil]

> How "test first, then code" works in a compiled language like C++ or Rust be beyond me

It's not really any different than in dynamic/interpreted/weakly-typed languages. "Writing the test" for a function sometimes just includes writing a method/function with the appropriate type signature that does nothing (maybe returns a dummy value).

Forcing you to view the code you're implementing from the viewpoint of someone calling that code from the very beginning is one of the advantages/goals of TDD. If you find that it's difficult to set up the objects/data you need to write a test, eg, your code has a bunch of implicit dependencies on other components being in a particular state or it takes a ton of arguments that all have to be constructed, that's usually a strong indicator that you should rethink the design. You're getting early feedback on your API design before you waste time implementing it.