title: Make babel exclude test files
body: <p>On my build step I'm using babel to transpile the code to es5 (from <code>src</code> to <code>dist</code>). How do I make it exclude files ending in <code>.test.js</code>?</p>
  
  <p>package.json</p>
  
  <pre><code>"scripts": {
    "build": "babel src --out-dir dist",
  </code></pre>
  
  <p>.babelrc</p>
  
  <pre><code>{
    "presets": [ "es2015" ],
    "ignore": "\\.test\\.js"
  }
  </code></pre>