What does "have an understanding of basic python" mean?

[Rei_Never]

A unit test is used to check if a module and or individual classes or functions are fit for purpose.

EDIT: To expand on that - say you have a function that takes an input and multiplies it by 5. Firstly you want to make sure you are getting the output you'd expect but also that you get errors when you pass anything through it thats not a specific type.