No, not that Red Green!
Even a thoroughly-tested application can wreck havoc if it hasn’t been tested in the context of a production-like system under production-like conditions.
Tools like Puppet and Chef make it easy to produce a production-like environment for testing, but what about the production-like conditions?
One aspect of these conditions can be approximated with load testing tools like JMeter or The Grinder. I recently used The Grinder to troubleshoot a performance problem with a small web application. Here’s a walkthrough of my process.