[Bug]:

[kpeters-cbsi]

Version

27.5.1

Steps to reproduce

1. Clone repo at https://github.com/kpeters-cbsi/jest-fails-to-mock-selenium-webdriver
2. yarn install
3. yarn test

Expected behavior

I expect the test to complete successfully.

Actual behavior

 FAIL  test/index.ts
  ● Test suite failed to run

    TypeError: name.startsWith is not a function

      at ModuleMocker._createMockFunction (node_modules/jest-mock/build/index.js:594:22)
          at Array.forEach (<anonymous>)

Additional context

I did a bit of debugging on my own, and I think this is happening in _createMockFunction:

    if (name && name.startsWith(boundFunctionPrefix)) { <--- HERE
      do {
        name = name.substring(boundFunctionPrefix.length);
        // Call bind() just to alter the function name.
        bindCall = '.bind(null)';
      } while (name && name.startsWith(boundFunctionPrefix));
    }

Something in selenium-webdriver has a name property that's a function, rather than a string, which is causing that error. I wasn't able to figure out which class in selenium-webdriver was the culprit, however.

Environment

System:
    OS: macOS 11.6
    CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
  Binaries:
    Node: 14.19.0 - ~/.nvm/versions/node/v14.19.0/bin/node
    Yarn: 3.2.0 - ~/.nvm/versions/node/v14.19.0/bin/yarn
    npm: 8.5.5 - ~/.nvm/versions/node/v14.19.0/bin/npm
  npmPackages:
    jest: ^27.5.1 => 27.5.1

[SimenB]

This is due to https://github.com/SeleniumHQ/selenium/blob/8b53734fd2bc97f7d084dc8326bf4b6c47b7052e/javascript/node/selenium-webdriver/lib/by.js#L205-L207 messing with our logic for gettting the name of a function here: https://github.com/facebook/jest/blob/1cce9a7dc194103576fad6c2086052efbea5ae77/packages/jest-mock/src/index.ts#L974-L975.

It looks weird in Node's REPL as well.

It is also an error in typescript:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function/name#function_names_in_classes

[SimenB]

https://github.com/facebook/jest/releases/tag/v28.0.0-alpha.9

[github-actions]

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