BUG: if Promise doesn’t complete, remains waiting (instead of timeout)

[akauppi]

Steps:

Change this line to have a doc ID that doesn't get changed:

    await expect( waitForIt("projects/1/userInfo/abc_") ).resolves.toContainObject(william);

$ npm test

Expected:

• test should fail
• user should get back to command line prompt

Actual:

• execution does not return to command line

[akauppi]

The problem is that there's no timeout in the Promise, and JavaScript promises cannot be cancelled from outside.

[akauppi]

Suggestion for a work-around:

If we’re able to detect when the Jest environment has been torn down, make a setTimeout callback check that every 100ms or so, and cancel the Promise ”from within” if the environment is down.

This won’t allow us to change a timeout (in the reports) to success/fail, but it should be enough to let the execution pass (focus of the issue).

…aaand we can know the environment is down simply by making an �afterAll�

[akauppi]

jestjs/jest#9685

[akauppi]

Could bring eventually back, maybe as:

eventually.doc(docPath)

[akauppi]

Did a small experiment; can indeed tap into the afterAll and have the execution return to OS. (however...)

The thing keeping Jest from returning the control is the Firebase listener; not an unresolved Promise (Jest seems fine with those).

A suitable solution can be done. Since this repo is about Firebase / Jest interaction, this might be as good a place as any to do it.

(ultimately, Firebase could be more Jest friendly?)

[akauppi]

Fixed in 05b1eb9, coming to next release.

The fix wraps .onSnapshot so that the programming API remains the normal for tests, but if there are unreleased listeners when Jest exits, those are released.