Considering there are many other APIs available to solve this problem I don't think this is a glaring issue. I only linked the one I did because it was straightforward to use and simple.

Okay, due to computation time constraints set by codewars, (12000ms) I only added 3 random test cases on top of the regular test cases. Should be up to par now though!

so in this case, have a random assortment of letters generated every test and use that as test input?

There are many APIs you could use to solve this problem. I just found a very straightforward and easy one to use and linked it.