I will explain why would we want to write tests, how to write them (in WordPress and a plugin setting) and how this changed my life. I have experience with unit-testing (WordPress, GlotPress, before), and I am one of the maintainers/committers in the current test framework.
Check out Nikolay’s slides: Unit Testing Will Change Your Life
About the Speaker:
Nikolay is a long-time WordPress core contributor, lives in Bulgaria, works for Automattic, and has a bear.