You may also have some interesting read about the argoument:
good thread about testing and habits.
Testing methodology, best practices and a pig in a hut. by BrowserUk who point to
http://www.sqetraining.com/sites/default/files/articles/XDD8375filelistfilename1_0.pdf
Tux about refactoring code and Test driven designL*
There are no rules, there are no thumbs..
Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.