Alright. I am not entirely sure the reason behind it, but it turns out you cannot call the function in the describe/2 block, but you can call it in the test/1 block. I am not really sure of the limitations on this because I was able to call List.first/1 without an issue. So maybe it is limited to functions defined in the same exs file?
Either way, what you should be doing is using a setup_all/1 block in order to do something for all of the tests within the describe/2.
