The "Drupal Extension to Behat and Mink" provides some nice Drupal specific step definitions and ways of setting test data up. This post runs through the setup process.

Getting a screenshot and a dump of the HTML of a failed step is invaluable when running tests on a headless "browser" like PhantomJS, and this post will show you how

Writing tests should be easy, but installing and maintaining every single piece needed is nontrivial. Thankfully Docker can provide each piece of the jigsaw: Symfony 3, Behat and PhantomJS.