So generally, I write a test when I want to make an assumption an certainty. If I can't be certain that something is doing what it's supposed to I write a test

So generally, I write a test when I want to make an assumption an certainty. If I can't be certain that something is doing what it's supposed to I write a test for it, make sense? So ``` Int => add(x, y) => x + y; ``` Doesn't get a test, however ``` Int => formulateIt(x, y) => (x * y)^y ``` Does