Having mocked function return something else than undefined?

[chenglou]

I've bitten by Jest a few times now trying to alter an existing module and find the test broken, because one random function is now mocked and returns undefined. I know I should have checked the mocked list, but unfortunately this doesn't come naturally.

I was wondering if we can return something like new Error('This function is mocked, do not use its return value') instead? This is just a wild idea. This would actually break things if, say, you store the return value in a map. But along this line, is there a way to warn the user about this?

[ghost]

Thank you for reporting this issue and appreciate your patience. We've notified the core team for an update on this issue. We're looking for a response within the next 30 days or the issue may be closed.

[cpojer]

Unfortunately I don't think there is anything we can do about this. I'm going to close it out but feel free to reopen if you can think of a good fix for this! I agree it would be great if we could have a solution here.

[github-actions]

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