title: Jest finds tests but doesn't collect coverage
body: <p>I trying to collect test coverage for <a href="https://github.com/lualparedes/lualparedes.github.io" rel="noreferrer">this project</a> using</p>
  
  <pre class="lang-sh prettyprint-override"><code>yarn test --coverage # i.e. "react-scripts test --coverage"
  </code></pre>
  
  <p>My jest config is this:</p>
  
  <pre><code>  "jest": {
      "collectCoverageFrom": [
        "src/**/*.ts*"
      ],
      "coverageThreshold": {
        "global": {
          "lines": 90,
          "statements": 90
        }
      }
    }
  </code></pre>
  
  <p>and my folder structure is as follows:</p>
  
  <pre><code>.
  ├── package.json
  ├── postcss.config.js
  ├── public/
  ├── README.md
  ├── src/
  │   ├── App.css
  │   ├── App.test.tsx
  │   ├── App.tsx
  │   ├── assets/
  │   ├── components/
  │   │   ├── Emoji/
  │   │   │   ├── Emoji.test.tsx
  │   │   │   ├── Emoji.tsx
  │   │   │   └── index.ts
  │   │   └── Home/
  │   │       ├── Home.css
  │   │       ├── Home.test.tsx
  │   │       ├── Home.tsx
  │   │       └── index.ts
  │   ├── index.css
  │   ├── index.tsx
  │   ├── react-app-env.d.ts
  │   └── serviceWorker.ts
  ├── tsconfig.json
  ├── yarn-error.log
  └── yarn.lock
  </code></pre>
  
  <p>Jest is being able to find all the tests but it fails to collect coverage:</p>
  
  <pre><code> PASS  src/components/Home/Home.test.tsx
   PASS  src/components/Emoji/Emoji.test.tsx
   PASS  src/App.test.tsx
  ----------|----------|----------|----------|----------|-------------------|
  File      |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
  ----------|----------|----------|----------|----------|-------------------|
  All files |        0 |        0 |        0 |        0 |                   |
  ----------|----------|----------|----------|----------|-------------------|
  
  Test Suites: 3 passed, 3 total
  Tests:       3 passed, 3 total
  Snapshots:   0 total
  Time:        3.432s
  Ran all test suites.
  </code></pre>
  
  <p>What am I missing? What should I add to the configuration to get the coverage?</p>
  
  <p><strong>Any hint is welcome :)</strong></p>
  
  <h2>Tries</h2>
  
  <ol>
  <li>Changing the glob pattern to <code>"src/**/*.{js,jsx,ts,tsx}"</code>.</li>
  <li>Removing <code>node_modules</code> and then running <code>yarn</code> to reinstall everything.</li>
  <li>Removing <code>node_modules</code> and <code>yarn.lock</code>, and then reinstall everything, which led to <a href="https://i.imgur.com/qfBEt4S.png" rel="noreferrer">another bug</a>, which I tried to solve installing that particular dependency, but it didn't work.</li>
  <li>Cloning the repository from GitHub and then running the command on the fresh version.</li>
  <li>Switching to a different Node version (v10.16.2, and v11.7.0).</li>
  </ol>