This is actually the type of system (especially if it's very rough code quality wise in many places) I think regression tests are very useful (tests to make sur

This is actually the type of system (especially if it's very rough code quality wise in many places) I think regression tests are very useful (tests to make sure the system doesn't change function). A book called "Working effectively with legacy code" by Feathers is great for instrumenting and regression testing old code bases then changing them without breaking them. Non-aff link http://www.amazon.com/Working-Effectively-Legacy-Michael-Feathers/dp/0131177052/ref=sr_1_1?ie=UTF8&qid=1288192392&sr=8-1 http://www.amazon.com/Working-Effectively-Legacy-Michael-Fea...