Not by design, as it happens. I wrote some new tests for code written in Arc, and stuck them into a separate file because I hadn't gotten around to implementing a mechanism to load Arc code without running the tests.
Though I do view writing dependencies-first as a form of scaffolding. You may need or want scaffolding for safety, or because you're working on a large project, or because you're in the midst of rebuilding.
Does that mean that you always need to use scaffolding when you work on a project? Of course not. If you're getting along fine without scaffolding, then you don't need to worry about it.
Nor, just because you might need scaffolding in the future, does it mean that you have to build it right now. For example, if I had some code that I wanted to rebase to work on top of a different library, and it wasn't in dependency order, and it looked like the rebasing work might be hard, I'd probably put my code into dependency order first to make the task either. But, if I thought the rebasing was going to be easy, I might not bother. If I ran into trouble, then perhaps I'd backtrack, build my scaffolding, and try again.