Doing CodeKatas is all the rage lately. That´s great since widely accepted exercises are important to further the art. They provide a means of communication across platforms and allow to compare results which is part of any deliberate practice.

But CodeKatas suffer from their size. They are intentionally small, so they can be done again and again. Repetition helps to build habit and to dig deeper. Over time ever new nuances of the problem or one´s approach become visible.

On the other hand, though, their small size limits the methods, techniques, technologies that can be applied. To improve your TDD skills doing CodeKatas might be enough. But what about other skills? Developing on a software in a team, designing larger pieces of software, iteratively releasing software… all this and more is kinda hard to train using the tiny CodeKata problems.

That´s why I´d like to present here another kind of kata I call Application Kata (or just AppKata).

AppKatas are larger programming problems. They require the development of “whole” applications, i.e. not just one class or method, but bunches of classes accessible through a user interface. Also AppKata problems always are split into iterations. To get the most out of them, just look at the requirements of one iteration at a time. This way you´re closer to reality where requirements evolve in unexpected ways.

So if you´re looking for more of a challenge for your software development skills, check out these AppKatas – or invent your own.

AppKatas are platform independent like CodeKatas. Use whatever programming language and IDE you like. Also use whatever approach to software development you like. Just be sensitive to how easy it is to evolve your code across iterations. Reflect on what went well and what not. Compare your solutions with others. Or – for even more challenge – go for the “Coding Carousel” (see below).

CSV Viewer

An application to view CSV files. Sounds easy, but watch out! Requirements sometimes drastically change if the customer is happy with what you delivered.

• Iteration 1
• Iteration 2
• Iteration 3
• Iteration 4
• Iteration 5 (to come)

Questionnaire

If you like GUI programming, this AppKata might be for you. It´s about an app to let people fill out questionnaires. Also this problem might be interestin for you, if you´re into DDD.

• Iteration 1
• Iteration 2 (to come)
• Iteration 3 (to come)
• Iteration 4 (to come)

Tic Tac Toe

For developers who like game programming. Although Tic Tac Toe is a trivial game, this AppKata poses some interesting infrastructure challenges. The GUI, however, stays simple; leave any 3D ambitions at home ;-)

• Iteration 1
• Iteration 2 (to come)
• Iteration 3 (to come)
• Iteration 4 (to come)
• Iteration 5 (to come)

Coding Carousel

There are many ways you can do AppKatas. Work on them alone or in a team, pitch several devs against each other in an AppKata contest – or go around in a Coding Carousel.

For the Coding Carousel you need at least 3 dev teams (regardless of size). All teams work on the same iteration at the same time.

But here´s the trick: After each iteration the teams swap their code. Whatever they did for iteration n will be the basis for changes another team has to apply in iteration n+1.

The code is going around the teams like in a carousel.

I promise you, that´s gonna be fun! :-)