title: What is the difference between `before()` and `beforeEach()`?
body: <p>What specifically is the difference between <a href="http://visionmedia.github.io/mocha/" rel="noreferrer">Mocha</a>'s <code>before()</code> and <code>beforeEach()</code>? (Same question for <code>after()</code> and <code>afterEach()</code>.)</p>
  
  <p>I assume <code>before()</code> runs once per <code>describe()</code> block, and <code>beforeEach()</code> runs once per test (<code>it()</code> block). Is that true?</p>
  
  <p>And when would I choose to use one over the other?</p>