So here is the challenge. Starting Wednesday 26th Dec and for the following 12 days I'm going to do just one kata per day. I'm calling it the 12 TDDs of Christmas and it would be pretty cool if a few other people out there took up the challenge with me 0 fancy it?

The 12 days started on December 26th, so there's a little catch up work to do, but you're not too far behind. The "katas" are short problems to solve that only require a bit of code to get working. The idea, though, is that you practice with the test-first methods and use these examples as the assertions.

Calisthenics is a Greek-derived term for exercises, in the gym sense. I have object calisthenics, exercises for object-oriented programming, around for a long time and saw them as fascinating, but never got the time to try.

The challenge he lays out includes rules relating to indentation levels (really complexity levels), wrapping primitives in strings, small entities and using first-class collections. To illustrate, he works through a solution to the prime factors kata and breaks it down into the eight different rules complete with code examples.