title: Global `before` and `beforeEach` for mocha?
body: <p>I'm using mocha for javascript unit-testing now. </p>
  
  <p>I have several test files, each file has a <code>before</code> and <code>beforeEach</code>, but they are exactly the same.</p>
  
  <p>How do I provide a global <code>before</code> and <code>beforeEach</code> for all of them (or some of them)?</p>