Missing async/await in chapter6/5_web_sockets_and_http_requests/1_http_request

[akaigyouhou]

I think there maybe some problem after you add fetch in addItem function in inventoryController.js for tests involving HTTP requests.
I got the error that the nock mock is not received request. And finally I think the problem is because you add a fetch in addItem function, but forgot to change the function to some async/await. But here is a problem, if you change the addItem function to async/await, the main.test.js will also be broken. And I am also not sure whether it's necessary to write some loop to to catch the fireEvent result after change the addItem function.