This is to make a step towards satisfaction of Dependency Inversion Principle. It's not fully satisfied because we still depend on concrete instances of classes instead of interfaces.
This will start chain of thought to pursue warm and friendly unit testing and introduction of SOLID principles.
Signed-off-by: Janne Savolainen <janne.savolainen@live.fi>
Co-authored-by: Mikko Aspiala <mikko.aspiala@gmail.com>
