If you’re looking to get started with unit testing in Objective-C, check out this screencast I created on testing with the XCTest Framework. It goes over the basics of assertions with XCTest, and you can follow along writing tests yourself to learn how it works. There’s no good excuse for not unit testing your Objective-C code – as you’ll see, it’s really easy to set up, Xcode has excellent support for it, and writing tests is just like writing production code.
Want to know how to unit test in Swift, too? Read my article on Unit Testing in Swift.