Before test runs, fails on CCI pipeline: "TypeError: Cannot read property 'createEvent' of null"

Question

I have tried researching other topics similar to this error message ( such as from here, here, here among others. ):

TypeError: Cannot read property 'createEvent' of null

In our test suit we have a lot of mocked network calls as a single mocking layer, but there is a throw new Error('unexpected URL') handler for missing calls. Also, I have verified all of my ReactTesting findBy queries are correctly declared with async/await syntax. Sometimes the tests work, othertimes fails.

What is really curious, is the error happens ONLY in Circle CI before any tests run, it appears, based on the error message call stack:

#!/bin/bash -eo pipefail
yarn test:ci
yarn run v1.22.11
$ jest --ci --runInBand
/home/circleci/project/node_modules/react-dom/cjs/react-dom.development.js:3905
      var evt = document.createEvent('Event');
                         ^

TypeError: Cannot read property 'createEvent' of null
    at Object.invokeGuardedCallbackDev (/home/circleci/project/node_modules/react-dom/cjs/react-dom.development.js:3905:26)
    at invokeGuardedCallback (/home/circleci/project/node_modules/react-dom/cjs/react-dom.development.js:4056:31)
    at flushPassiveEffectsImpl (/home/circleci/project/node_modules/react-dom/cjs/react-dom.development.js:23543:11)
    at unstable_runWithPriority (/home/circleci/project/node_modules/react-dom/node_modules/scheduler/cjs/scheduler.development.js:468:12)
    at runWithPriority$1 (/home/circleci/project/node_modules/react-dom/cjs/react-dom.development.js:11276:10)
    at flushPassiveEffects (/home/circleci/project/node_modules/react-dom/cjs/react-dom.development.js:23447:14)
    at Object.<anonymous>.flushWork (/home/circleci/project/node_modules/react-dom/cjs/react-dom-test-utils.development.js:992:10)
    at Immediate.<anonymous> (/home/circleci/project/node_modules/react-dom/cjs/react-dom-test-utils.development.js:1003:11)
    at processImmediate (internal/timers.js:464:21)
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

Exited with code exit status 1
CircleCI received exit code 1

I have not seen this error locally, even when running the same command as my Circle CI command.

Any ideas about this, other than unhandled

Answer 1

Can you try this. async() await and use expect() function and also catch the execption by new Error Object.

it("Should ...", async () => {
  await myFn(async () => {
    // some operations
    expect(await element.length).toBe(10).toThrow(new Error("something went wrong!"))
  });
});