title: How to ignore certain files when running `npm test` in create-react-app?
body: <p>Currently <code>npm test</code> is running all files that has <code>.test.js</code> extension. I would like some files to be ignored. Where do I configure that option? I tried </p>
  
  <pre><code> "jest": {
          "collectCoverageFrom": [
              "src/App.test.js"
          ]
      },
  </code></pre>
  
  <p>in package.json.
  I don't see any difference.</p>