Triangle type kata

Run the app

composer install
php app.php triangle:find-type 1.21 1.23 1.22

Run tests

composer install
vendor/bin/phpunit

Design decisions

Model

I have used inheritance to describe the three triangles as the different lengths information is inherent to the triangle itself, as well as the type.

I have used composition to describe the triangles, as it offers the opportunity to encapsulate all the responsibilities in each Value Object.

This way:

• Triangle is composed with a TriangleSides VO.
• TriangleSides is compose with three TriangleSide VO and has the responsibility of calculating the difference.
• TriangleSides enforces lengths validity.

I have also decided to create a factory to decouple creation of the Triangle from the Triangle itself, but a factory method in the Triangle would have also seem ok to me.

Layering

• Used hexagonal layering for decouple model from application and UI.

Testing

• No need to use mocks, everything is sociable unit tested.
• Creation of stubs for the reason of easier test code refactoring.