adding setupSinon function to dummy/index.d.ts to allow for types in …

[robostheimer]

…default import

All tests pass.
ember ts:precompile shows no errors.

[elwayman02]

This won't be a Partial anymore, right?

[elwayman02]

Actually, nvm, I think Partial is the right way to type it because they may in theory supply their own modified test environment with the same two methods to hook into.

[robostheimer]

In that case, I think that we’d want to with our own interface, given that we do not know for sure the their test environment is QUnit but we do know the methods they will be using.

interface TestEnvironmentInterface {
  testStart: (callback: () => void) => void
  testDone: (callback: () => void) => void
}

All that said the addon is called ember-sinon-qunit so aren’t we implying consumers will be using QUnit.

[elwayman02]

I think it's fine. If we run into a legit use-case, we can always go back and modify the types in a later release.