The REPL in (Lisp) driven development is generally attached to your editor, not like irb or ipython or whatever: so the thing you're building is either the resu

The REPL in (Lisp) driven development is generally attached to your editor, not like irb or ipython or whatever: so the thing you're building is either the resulting function, or something that mostly looks like a test already anyway and is easy to copy into a test module.