The Bowling Game Kata – First attempt

Last week I did a presentation about the Bowling Game kata in C#.

I created a repository on GitHub with the code so I can share my first attempt.

You can follow the commit comments to get an idea of the train of thought.

Or if u prefer, just keep reading

The Methodology

I used TDD and somehow BDD all the way. Started with an acceptance test and jumped in and out from the unit tests until the feature passed.

Why is a good idea to start with an acceptance test?

When you know where you want to go, what you want to achieve, is easier to keep the focus.

Having a way of identifying if the current feature is finished is a lot of power in your hands, so do the minimum necessary to make it work and then – once the test is passing – do refactoring as you see fit.

In the solution you will find three projects:

1. BowlingKata: Classes that implement the Kata
2. BowlingKata.Unit.Tests: Unit tests
3. BowlingKata.Acceptance.Test: Features that I’m looking for in a bowling game

Design Decisions (fast forward TDD)

As soon as I started to write a unit test for the BowlingGame class I wonder how am I going to design the solution.

My first test was for the method Roll(pins). And right there I had to assign responsibilities.

What should this method do? Do the “registration” only? Do the calculation as well? Is there any other class involved?

I decided on keep things simple and separate two clear responsibilities:

1. Keeping the number of pins knocked down on each ball (or frames later)
2. Calculating the score based on the information on each frame