I think most functional programmers don't use TDD. Instead, they write little functions (and macros) that do useful things and approach the problem bottom up, c

I think most functional programmers don't use TDD. Instead, they write little functions (and macros) that do useful things and approach the problem bottom up, constantly trying things out on the REPL and rewriting the code they have already written. This way of programming seems incompatible with TDD and I would recommend practicing it in order to start thinking functional. Paul Graham talks about it here: http://www.paulgraham.com/progbot.html http://www.paulgraham.com/progbot.html I don't program in Lisp or any other functional language, but I use this style a lot programming in Python and code ends up being pretty functional.