If you are a software developer, you might have come across the term "testable code". Almost always when someone refers to it they do it in the context of unit testing. So in order to understand, and then learn to how to write, testable code, you first have to understand unit testing. And this is what this talk is all about.

Thorsten first provides a high-level overview of unit testing in general, and classifies it in terms of test level, and testing methods and techniques. He then explores and explains different possible units. The second part of the talk is dominated by one of the key principles of unit testing: testing in isolation. What is it? How can it be done? What is this mocking that pops up here and there? Next, Thorsten shows different unit test examples, involving both PHP and JavaScript, and highlighting different (yet simplified) aspects of real-life code. Thorsten concludes with a few tips for writing good unit tests.