title: Unit Testing using mocha, node
body: <p>I'm new to unit testing in the Node world and am struggling with this: I've setup a after cb to delete the records I've added during my tests, however I keep getting an error <code>Error: done() called multiple times</code> every time I delete the record on the db. Here's my code:</p>
  
  <pre><code>after((done) =&gt; {
      User.deleteOne({email: user_email}, function(err, result) {
          if(err) console.log(err);
          console.log(result);
          done();
      });
  });
  </code></pre>
  
  <p>If I do anything else (like just console something within the <code>after</code> block, I get no error at all.</p>
  
  <p>What am I doing wrong?</p>