DI with Application.get_env is just too much of a ceremony sometimes. Particularly I consider a behaviour with a single prod implementation that is there just for testing as a lot of ceremony.
The example I have shown doesn’t require any code changes for testing. And whatever Martin Fowler did in the blog post didn’t affect the interface - i.e. no changes to the PriceCalculator clients were needed.
I’d strongly suggest not getting hung up on the inheritance portion of this. It’s imo irrelevant to what that blog post tries to teach.
Agreed. It’s a specific technic that satisfies a number of constraints and the whole purpose of my question is to understand if there is a similar technic that we can use in Elixir codebases. Not a DI through explicitly passing collaborators or making them swappable via application config.
I hope it’s clear what I’m asking.
