Test Driving Legacy Code

One of the first roadblocks people encounter to adopt TDD is that we seldom have the luxury of working on clean, greenfield code bases. Instead, we have a messy ecosystem of “legacy systems” in various states of disrepair and fragility. We then have a situation where the main outcome of TDD (that is, allowing us to introduce changes and new features with confidence) would be very beneficial, yet it seems that legacy code actively works against our attempts to write that initial failing test to get started!

In this session, we’ll go over two techniques to help you get started with a Test Driven approach to working with legacy code: the Golden Master, and Characterization Tests.

The session will be mostly interactive and hands-on, so please bring your laptops and expect to pair with other participants. We’ll be using the Cyber-Dojo online coding environment (http://cyber-dojo.org); no particular development environment will be required.

If you’re already an experienced TDD practitioner, we encourage you to come and help us mentor other TDD enthusiasts.