Doing Code Katas alone or in a Dojo can help sharpen our elementary skills as software developers. Practicing IDE shortcuts and TDD mini-step cycles is very useful for the daily business, yet I find some existing Code Katas too far away from real-life programming situations. That’s why I came up with the Trading Card Game Kata – which is (very loosely) based on Blizzard Entertainment’s free-to-play online-game “Hearthstone – Heroes of Warcraft”. This Kata is focused on practicing TDD in a slightly more complex (but not complicated) situation where you might have to think about rules like Single Responsibility Principle or Command Query Separation and might even feel the urge to use a Mocking framework at some point.
First I will introduce the ideas of Katas and Dojos in general and explain the TCG Kata rules to you. Then I will demo some real-life best-practices for writing good developer tests, using my TCG Kata sample solution as a showcase. This will include:
- Picking the right Test Double
- Test Data Builders
- Behavior Tests with BDDMockito
- Prose-like Assertions with Hamcrest
- Readability Sugar
The full Kata ruleset and a sample solution in Java 8 can be found on https://github.com/bkimminich/kata-tcg.