How to test next-auth middleware?

[flacial]

I'm having difficulties testing its middleware. Usually when I write the tests of something, it has functions I can mock and test if they were just called with our without certain value. In the case of next-auth, I'd like to test the signIn callback, but:

NextAuth returns this:

Promise {
  <pending>,
  [Symbol(async_id_symbol)]: 121983,
  [Symbol(trigger_async_id_symbol)]: 121973,
  [Symbol(destroyed)]: { destroyed: false }
}

Oh, it's a promise, it makes sense to await or .then it:

undefined

Even its function return type is any. So, I'm not certain. Is there a way to test or we should ignore it in the code coverage somehow?

Useful link of it being tested with Cypress: https://next-auth.js.org/tutorials/testing-with-cypress I think Cypress is used for E2E tests which we don't have yet I think.

[songz]

FYI When struggling with unit test, the correct solution isn't "let's add functional test". It works, but it hides the underlying problem which is that we want to figure out a way to unit test the function.

I don't think we need to test the return value of nextauth middleware, but rather what we pass into nextauth right via the callbacks? If so, we just need to test the callback functions.

Example (about signInCallback)

export const signInCallback = async ({ user, account, profile, email, credentials }) {
      ...
}

...
  callbacks: {
    signIn: signinCallback,
    ...
...
}

In your test you'd just test signInCallback right?

[flacial]

Yeah. Thanks for the help!