jest.useRealTimers() is not a function when running RTL tests in jest-electron environment

[Manish3323]

I decided to try using jest-electron environment in our jest test setup because jsdom environment has some missing browser functionality that we were using.

• "@testing-library/jest-dom": "^5.11.9",
• "@testing-library/react": "^11.2.3",
• "@testing-library/user-event": "^12.6.3",
• node version: v15.10
• npm version: v7

Relevant code or config:

pasting only necessary changes here of my jest.config.js

{
 .
 .
  runner: 'jest-electron/runner',
  testEnvironment: 'jest-electron/environment',
  .
  .
  .
}

What you did:

ran npm run test

What happened:

i think helpers file inside RTL /dom is calling jest.useFakeTimers()..
which is not available in jest-electron environment.

The error that i'm getting is shown in the following SS.

Reproduction:

Small repro can be created on local machine on following these steps.
clone : https://github.com/tmtsoftware/esw-ocs-eng-ui
git checkout jest-branch
npm i & npm t

Problem description:

RTL/jest-dom helpers are calling jest.timers functionality without checking jest-environment.

Suggested solution:

there could be some kind of check related to which environment jest is currently running before this line.
@Testing-Library/dom/dist/helpers.js:38.

[SimenB]

Seems to be an issue with the env: https://github.com/hustcc/jest-electron/blob/b5887476eb639549c9317dd26b839d961ac58573/src/environment.ts#L38-L43

we could probably add better support for custom envs not supporting all helpers. Jest only really works well with custom envs that extend the default ones.

[EsoterikStare]

I'm running into a similar issue when trying to upgrade the mui-org/material-ui dependency from @testing-library/dom@7.22.1 to @testing-library/dom@7.28.1 and above. After that upgrade, I get the exact same error mentioned here.

The issue is that when helpers.js checks if typeof jest !== 'undefined', it's actually true because jest is null at this point for some reason, which has a type of object (thanks js), so it makes it past that check.

Later, when it tries to call jest.useRealTimers(); it errors, because jest is null and has no such property to invoke.

This is not the case before the upgrade and it is the case after the upgrade, and I've checked to make sure there are no other changes to the dependencies so it seems like it's a direct result of changes between those versions.

Some other relevant info for this scenario:

• MUI uses mocha, not jest, so the jest binary isn't even defined anywhere in the repo context. (I've also ensured it's not installed globally and isn't defined in the test execution context at all.)
• Because jest is not in play at all, there is no testEnvironment set. NODE_ENV is being used to drive some functionality, but seems completely unrelated.

This issue I'm having may be unrelated, but it seems very similar and I'm really scratching my head to understand this issue.

@Manish3323, could you inspect the type and/or value of jest right before that check in the helpers.js file by tossing a console in node_modules code? Just curious what the value might be. That check is clearly not catching all bad cases.

[eps1lon]

@EsoterikStare What we're doing in Material-UI is quite esoteric (gotta make that pun) and not really relevant here. Let's discuss this in the mui-org repo.

What Material-UI is doing: React only triggers unexected act warnings when typeof jest !== 'undefined' so we're just setting it to null to get them. We don't have any problems with dom-testing-library since we don't rely on waitFor and the general advise is to not use waitFor in our component tests. Component-library tests have different requirements than component-app tests.

[EsoterikStare]

esoteric (gotta make that pun)

@eps1lon Got it! Thanks!

[ZheyangSong]

In case this helps anyone facing the same issue, this breakage is seemly introduced by a patch version of 7.29. You can try to downgrade this library to a 7.28.x or lower. You should get this issue gone.

Hope this will get the testing-library project team's attention as well. For me, the module I use, its custom environment doesn't define userRealTimers. https://github.com/facebook-atom/jest-electron-runner/blob/master/packages/electron/src/Environment.js#L16

[eps1lon]

@Manish3323 Thanks for the repro. This helped a lot verify the fix.

[github-actions]

🎉 This issue has been resolved in version 7.30.4 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[Manish3323]

@eps1lon.. thanks for looking into this 🙌 ..
i have updated all my package dep's to their latest versions..(basically ran npm-check-updates -u)
the error mentioned above persists..
what am i missing ?