Templetize tests

[wilsonehusin]

I'm here to repay my sins of the terrible tests I wrote. I promised to do this before the next ticket at standup, because it would have been much messier PR without fixing these first.

Test files (both golden and mock API response) now all have conventions.

You can think of it like frontend snapshot testing — we should always produce exactly the same data (whether it's database entry or rendered Terraform) for the same input. Model structs, database rows, HCL — they are all just spicy JSON really.

This approach makes it easier to write tests, which hopefully incentivizes higher accuracy of tests, while still providing good signal on per test.

[AlexisJasso]

Having now looked at the old tests in more detail, I see the improvements here and I like it.