(#8581) - Fix this of changesHandler

[vrtmrz]

Fix this of changesHandler.

The test is also written but works only for browsers.

[janl]

@vrtmrz thank you for this. Unfortunately the test fails in CI: https://github.com/pouchdb/pouchdb/actions/runs/4063298839/jobs/6995899992 — I’m not sure I understand the error message about number of assertions either. Is there something you could do?

[vrtmrz]

Thank you for pointing it out!
I am not sure about the value that assertion detected. However, we may also have timing problems.
I have rewritten the function to a callback style and will test it again.

[vrtmrz]

I have checked this test again. The assertion error you pointed out was probably not a problem with this test itself.
Perhaps, test.viewadapter.js is not waiting for both of onsuccess, and this test detects it.
I have not tested these assumptions, but I think we need to address and call done() or wrap events to Promise and await.

The browser-side tests became can be passed. May I ask you to review it again?