title: CSS module @import fails the Jest test suit
body: <p>I am using Jest and Enzyme to test my application. I am getting error:</p>
  
  <pre><code> FAIL  app/containers/Navbar/NavbarContainer.test.js
    ● Test suite failed to run
  
      app/components/Navbar/styles.css: Unexpected token (1:0)
        &gt; 1 | @import "../../styles/base/_variables";
            | ^
          2 |
          3 | .navbar{
          4 |   width: $navbar-width;
  </code></pre>
  
  <p>This is my Jest configuration in package.json:</p>
  
  <pre><code>"jest": {
      "verbose": true,
      "globals": {
        "env": {
          "isProd": false,
          "isDev": true,
          "command": "start"
        }
      },
      "moduleNameMapper": {
        "\\.(css)$": "identity-obj-proxy"
      },
      "moduleFileExtensions": [
        "js",
        "jsx",
        "json",
        "css"
      ],
      "modulePaths": [
        "/app"
      ],
      "moduleDirectories": [
        "node_modules"
      ],
      "verbose": true,
      "setupFiles": [
        "./setupJest.js"
      ],
      "setupTestFrameworkScriptFile": "&lt;rootDir&gt;/setupTests.js"
    }
  </code></pre>
  
  <p>I was following the guides while setting up the application, and I found that <code>identity-obj-proxy</code> will help to mock css-modules functionality, but that's not working in my case. Please let me know what am I missing here.</p>
  
  <p>P.S. this is about not ES6 modules import. The suit failed because there is a <code>@import</code> in css.</p>