title: Mocha passing tests in browser, failing on command line
body: <p>I'm using mocha-grunt to be able to run/see my client side tests on the command line. For some reason, it seems that decrementColumn is being called twice when I run my tests on the command line. </p>
  
  <p>I wonder if some sort of phantomJS window scoping problem with beforeEach, because if I copy that block of code ( new Level instantiation) to the top of the decrementColumn test, everything works for both browser and command line. </p>
  
  <h2>FUNCTION</h2>
  
  <pre><code>decrementColumn: function( columnPosition ){
      --this.columns[ 0 ]
  },
  </code></pre>
  
  <h2>TEST</h2>
  
  <pre><code>describe( 'Level', function(){
      beforeEach( function(){
          level = new Level( [ 2, 3, 5 ] )
      })
  describe( '#decrementColumn()', function(){
      it( 'should reduce column by one', function(){
          level.decrementColumn( 1 )
          expect ( level.columns[ 0 ] ).to.equal( 1 )
      })
  })
  </code></pre>
  
  <p>})</p>
  
  <h2>GRUNTFILE</h2>
  
  <pre><code>module.exports = function( grunt ){
      grunt.initConfig({
          pkg: grunt.file.readJSON( 'package.json' ),
          mocha: {
              all: {
                  src: [ 'test/runner.html' ],
              },
              options: {
                  reporter: 'Spec',
                  run: true
              }
          }
      });
  
      grunt.loadNpmTasks( 'grunt-mocha' )
  
      grunt.registerTask( 'default', [ 'mocha' ] )
  };
  </code></pre>
  
  <h2>SPECRUNNER</h2>
  
  <pre><code>&lt;html&gt;
  &lt;head&gt;
      &lt;meta charset="utf-8"&gt;
      &lt;title&gt;Mocha Tests&lt;/title&gt;
      &lt;link rel="stylesheet" href="../lib/mocha.css" /&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;div id="mocha"&gt;&lt;/div&gt;
      &lt;!-- mocha dependencies --&gt;
      &lt;script type="text/javascript" src="../lib/jquery.min.js"&gt;&lt;/script&gt;
      &lt;script type="text/javascript" src="../lib/expect.js"&gt;&lt;/script&gt;
      &lt;script type="text/javascript" src="../lib/mocha.js"&gt;&lt;/script&gt;
      &lt;script type="text/javascript" src="../lib/chai.js"&gt;&lt;/script&gt;
  
      &lt;!-- application files --&gt;
      &lt;script type="text/javascript" src='../client/view.js'&gt;&lt;/script&gt;
      &lt;script type="text/javascript" src='../client/logic.js'&gt;&lt;/script&gt;
      &lt;script type="text/javascript" src='../client/level.js'&gt;&lt;/script&gt;
      &lt;script type="text/javascript" src='../client/game.js'&gt;&lt;/script&gt;
      &lt;script type="text/javascript" src='../client/init.js'&gt;&lt;/script&gt;
  
      &lt;!-- configure mocha &amp;&amp; chai --&gt;
      &lt;script&gt;
          mocha.setup( 'bdd' )
          expect = chai.expect
      &lt;/script&gt;
  
      &lt;!-- test files --&gt;
      &lt;script type="text/javascript" src='level-spec.js'&gt;&lt;/script&gt;
  
      &lt;script&gt;
          mocha.globals(['jQuery']);
          mocha.run();
      &lt;/script&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p><img src="https://cloud.githubusercontent.com/assets/3118416/3203034/26471ca2-ed97-11e3-9881-700db05e7714.png" alt="browser">
  <img src="https://cloud.githubusercontent.com/assets/3118416/3203036/27ed6372-ed97-11e3-9fb9-1ca290b238fa.png" alt="command line"></p>