[Due for payment 2025-07-18] Fix flaky tests in `ReportTest.ts`

[tgolen]

Problem

More context in this Slack thread

When writing the PR for #64279, the unit tests in this file began failing. The code in my PR doesn't change the logic of the de-duplication library, and it uses the same de-duplication method as some other API commands.

Therefore, we determined this is an issue with the unit tests specifically.

Solution

It appears like the tests need to be improved so that they run in complete isolation with nothing bleeding over between tests. @gedu I think you have the most context to fix this.

cc @adhorodyski

[gedu]

I will take a look at this soon

[gedu]

I'm still investigating this issue. I created a smaller test and ran only that one, and I found that the test stops working mainly when using
Onyx.set(${ONYXKEYS.COLLECTION.REPORT}${REPORT_ID}, {reportName: 'Test', reportID: REPORT_ID});. I'm currently investigating why this is happening.

[gedu]

@tgolen I just tried commenting out jest.useFakeTimers(); and it worked with the conflicting function. I think it's because Onyx.set() uses internal setTimeout for batching, which doesn't advance when using fake timers. Can you try commenting out or removing that line from the test to see if that fixes it?

[tgolen]

You're right! I confirm that after removing the fake timer, all the tests are passing now. So... it sounds like we should just remove that. It looks like we use it in 8 other places. Should we look into those at all and see if they are really necessary? I have no idea why it was added in ReportTest.ts.

[gedu]

That's awesome, I think if we are using some Onyx updates, we shouldn't await them if we add the useFakeTimers