Test Driven Development, Refactoring, Clean Code and Software Craftsmanship are all techniques and methods that produces high quality code in Oriented-Object Programming languages.
XSpec framework, and its integration in Oxygen, allows to apply test driven development with XSLT. It runs quickly enough to have a short TDD loop, and to produce quickly deliverable code.
Coding time is a little it more important than with standard method, but it produces code that is much cheaper to maintain, and much more reliable.
Mixing TDD and XSLT provides a lot of serinity to developers.