Performance tuning an application is time consuming, and expensive. Useful tests often need dedicated hardware to run on. It's specialised and time consuming to prepare the ground work and write the various fixtures needed to run, and whose only perceived benefit is preventing a production issue that you don't even know will happen yet.
This is a 5 minute tutorial on how to write a test story using EasyB, a Groovy based behaviour driven development system for Java.
You'll need Maven installed and you may want to have an IDE with Maven and Groovy integration. Additionally, both IntelliJ and Eclipse also provide EasyB plugins that allow you to run individual stories.
Firstly create a skeleton project, and add these plugins to your POM: