One of the coolest feature I came across in Elixir - our code documentation becomes our unit tests. I was amazed by its simplicity when I saw it in action in sample app I was writing. I feel this is one of the most incredibly and helpful feature I saw in any modern programming language in recent times. (Python has similar functionality using Python’s doctest.) Let me explain this by giving a quick demo using few simple examples: Math functions sum and multiply. Lets say this is our Maths module defmodule Maths do def sum(num1, num2) do num1