Why should I bother with unit testing if I can just use integration tests?

Question

Ok, I know I am going out on a limb making a statement like that, so my question is for everyone to convince me I am wrong. Take this scenario:

I have method A, which ca

Answer 1

Most of the problem is in the scenario you've posited -- according to your description, all B does is return null. Unit testing something that trivial probably is pretty pointless -- but is is writing the code to start with. If all you need is a null, use null directly and eliminate B completely. If B justifies its existence by really doing something more than return null, then the unit test you've described is incomplete, and you need to test whatever else B is supposed to do.