Make tests less boilerplate-y

[wokalski]

When I was reviewing #31 I noticed that the tests are extremely boilerplate-y without a need. They seem to be duplicated between tests, too. It'd be good to reduce this clutter because otherwise it's super hard to make sense of them.

[tsnobip]

yeah, I agree, what do you have in mind to improve the situation?

[wokalski]

I had the simplest idea to just make the atd files tiny. Like one line definitions type foo = { bar: string }