For decades functional programming has disappeared from industry mainstream. It’s great that these ideas around modeling applications have reappeared with a huge force, but it can be difficult to see how they fit into our current Agile teams. I’ve spent the last year and a half working to figure out if and how TDD and BDD fit with functional programming. To take it a step further, I’ll break down how agile practices fit in with Lisp vs ML style functional languages.