fix: free non contributor swag

[chadfawcett]

Currently anyone can request a discount code and redeem free swag. This resolves that by awaiting the response from isGitHubContributor.

api.gatsbyjs.org/routes/store.mjs

Line 21 in 8a4b73b

const contributor = await isGitHubContributor(username);

I've added some tests to hopefully catch any regressions. I'm not 💯happy with my tests. I refactored the mocks and fixtures for @octokit/rest in or to be more reusable. I would have preferred if I could have gotten the whole class auto mocked by jest and then add a mockImplementation for search.issues, but I couldn't get it working because it's a class. I might be able to take another crack at it with fresh eyes tomorrow.

The added routes/store tests work, but I'm not super happy with them either. I tried to test the router directly by calling express' router.handle function. The nice thing about it is that we don't have to spin up the app using something like supertest, but the downside is the callback-y-ness.

I wanted to submit the PR before heading off to bed, so I may do some refactoring tomorrow but I wanted to get your thoughts.

[jlengstorf]

This looks great. Thanks, @chadfawcett!

For the tests, this looks pretty good to me. Don't worry about the store route too much because I'm about to do a refactor to change this from a REST API to a GraphQL API, which means the routes are going to change very soon.

Thanks again!