feat: Testing

[theS1LV3R]

original issue on Linear

All services and routes need to be tested in order to minimize error rates.

Probably needs dependency injection to work.

See also:

• https://glebbahmutov.com/blog/how-to-correctly-unit-test-express-server/
• https://dev.to/nedsoft/testing-nodejs-express-api-with-jest-and-supertest-1km6

[theS1LV3R]

Both services and routes should be tested to minimize errors. Services first, to make sure they work as intended, and then routes. That way we know where something errored if it errors.