I was unable to co-present at DrupalCon San Francisco due to a volcanic ash cloud that prevented anyone from flying out of London for a week, so David Strauss did my part, along with Eric Baumes (CTO of The Economist). Thanks to, the presentation is available and you can see David doing an amazing job presenting our work. Presentation Session on
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, 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.
Economist developers are a big, distributed lot. At one point we had 4 teams doing development in 4 different timezones from San Francisco to London. As you might imagine, this presents some extremely interesting challenges, like source code control and maintaining communication channels between teams to reduce the amount of toe stepping and work duplication going on. Bazaar & Launchpad The single tool that has had the largest positive impact on code quality and general sanity has been Launchpad.
We enountered a strange issue yesterday with a mysterious disappearing cookie. It turned out that an invalid favicon.ico link was causing the issue. The Drupal CDN module rewrites the favicon link to be served from <?php <link rel="shortcut icon" href= "" type="image/x-icon" /> ?> The CDN, however, wasn't configured to serve .ico files, so it was issuing a redirect to (the home page). That caused weirdness with the favicon in general, although sometimes it would appear depending on the user's browser.
David Strauss and I are presenting the load testing work our team did at The Economist. Here's a link to the session information. UPDATE: I was unable to attend the conference, as all flights were cancelled following the volcanic eruption of Eyjafjallajökull :< I made a follow-up post here: Performance Testing Drupal