title: Jest - TypeError: Cannot read property 'fn' of undefined
body: <p>Out of nowhere, I'm having an issue when running certain Jest tests: </p>
  
  <pre><code>Summary of all failing tests
   FAIL  server/controllers/voice/settings/__tests__/voice.settings.controller.test.js
    ● Test suite failed to run
  
      TypeError: Cannot read property 'fn' of undefined
  
        at Runtime._createJestObjectFor (node_modules/jest-runner/node_modules/jest-runtime/build/index.js:734:35)
        at handle (node_modules/worker-farm/lib/child/index.js:44:8)
        at process.&lt;anonymous&gt; (node_modules/worker-farm/lib/child/index.js:51:3)
        at emitTwo (events.js:126:13)
        at process.emit (events.js:214:7)
  </code></pre>
  
  <p>I saw that someone had the same problem here (<a href="https://github.com/facebook/jest/issues/5058" rel="nofollow noreferrer">https://github.com/facebook/jest/issues/5058</a>) but I'm not sure if it ever got resolved. I tried removing node_modules and reinstalling but that didn't fix it. Wondering if anyone else has had the same error before and how it got resolved?</p>