CI

Selenium is an automated software testing framework for web applications. It drives a real browser automatically, as if a real person was doing the clicking and typing. We use it here at The Economist for functional / black-box / acceptance testing, the kind of tests that are repetitive and time-consuming to step through manually. We've setup a system that runs our full suite of regression tests in parallel, using virtual machines in the Rackspace cloud, on every commit to trunk.
You want to test your Drupal code? We’ve learned how to do it, the hard way, through 3 years of experience with continuous integration at The Economist. And I can distill our current approach into a few short paragraphs: 1. Use Simpletests to unit test code. Unit testing is vital, but it’s also difficult in Drupal, because a lot of time you’re actually writing glue code, or exporting Views, or theming.
Running an out-of-the-box stack like MAMP may be fine for part-time tinkerers, but if you're writing code for a serious site you'll quickly realise that it's important to develop against the same version of the stack that's running in the production environment. You'd be amazed at how many subtle bugs emerge between two minor point releases of PHP, APC, MySQL or any other of the myriad components. Catching them early is crucial, and the easiest way to do that is to use a virtualised developer environment.
We have a fun concept here that we call a “human test instance”. Anyone can create an entire copy of Economist.com, running in the cloud, on a subdomain of their choice, on a branch of their choice, with just a few clicks in Hudson. “Human testing” implies that the instance is used by a human to do manual testing, however, we use a human test instance to run automated Selenium tests, and each one also effectively tests the process of running the update functions every day.