This is a work in progress proposed fix to #19. I'll gradually add more tests but the foundation is there for now. As a quick overview of what I decided on using and how this all works, here's a small writeup:

The testing framework used is Intern. This allows using chai asserts which are easier to read in my opinion. As well as a close to zero configuration setup which lets us focus on writing tests instead of configuring things that aren't really necessary.

Furthermore, because we can't use electron or node_modules directly. We rely on testdouble which allows us to mock external dependencies by either:

1. stubbing the whole module with td.replace and then replacing single functions with td.when().then()
2. mocking objects in code and patching out single modules yourself. This is needed because electron itself relies on node modules and can't be stubbed easily. That's why object replacement is necessary.