no-test-callback autofix can produce invalid code

Hello team,

With the release of v23 our team had issues with the new recommended rules, and in particular no-test-callback.

test('my test', async (done) => {
  await myAsyncTask();
  expect(true).toBe(false);
  done();
});

This code is marked as Illegal usage of test callback which is a fair warning; I would say the done usage is more useless than illegal (but just a matter of wording here).

This code will be transformed to:

test('my test', async () => {await new Promise(done => {
  await myAsyncTask();
  expect(true).toBe(false);
  done();
})});

Which is:

• not very pretty
• invalid
  • as await now lives in non async method
  • if you put the async keyword you can encounter an other linter error no-async-promise-executor

---

This is not a bug nor an urgent matter, but I would be in favor of letting the user change his/her code instead of modifying the behaviour of the test without the user paying attention.

Have a great day,

[SimenB]

@G-Rath support released, if you wanna play with it: https://github.com/typescript-eslint/typescript-eslint/releases/tag/v2.9.0

[SimenB]

FWIW we should yell at this in Jest itself at runtime - you should either use the callback or return a promise, never both

EDIT: Opened up https://github.com/facebook/jest/pull/9129 for it