test: move the suite over to busted
Summary:
Right now we are using a custom test runner. This move the suite over to
busted, this will make things much more maintainable going forward. The two
main reasons for moving are.
- The custom runner as some bugs, when running assertions we are not getting
the correct results.
- All of the busted mocking features. We can use spy and mock, this will allow
us to remove the nvim_mock. This file is not amazing and confuses the lsp
often.
Test Plan:
CI