title: Mockgoose is downloading 234mb when running mockgoose.prepareStorage
body: <p>I have a node application with access to mongodb thrown mongoose tested with mocha and mockgoose.
  I moved recently to mockgoose 7.0.5.
  I followed the getting started on github and upped my mocha timeout to 2 minutes.</p>
  
  <p>Here are my before functions in my tests :</p>
  
  <pre><code>import mongoose from 'mongoose';
  var Mockgoose = require('mockgoose').Mockgoose;
  [...]
  
  const mockgoose = new Mockgoose(mongoose);
  
  before(function(done) {
    try {
      console.log('BEFORE prepareStorage');
      mockgoose.prepareStorage().then(() =&gt; {
      console.log('IN prepareStorage');
        mongoose.connect('mongodb://example.com/TestingDB', function(err) {
          done(err);
        });
      }).catch((error) =&gt; {
        done(error);
      });
    } catch(e) {
      done(e);
    }
    console.log('AFTER prepareStorage');  
  });
  
  beforeEach(function(done) {
    mockgoose.helper.reset();
    done();
  });
  </code></pre>
  
  <p>When I run the tests, during the <code>mockgoose.prepareStorage</code> step, mockgoose seems to be downloading something.</p>
  
  <pre><code>BEFORE prepareStorage
  AFTER prepareStorage
  Completed: 0.1 % (0.2mb / 234.3mb
  </code></pre>
  
  <p>I guess it has something to do with the requested 2 minutes timeout.</p>
  
  <p>My questions / problems are :</p>
  
  <ul>
  <li><p>Does anybody know what mockgoose is downloading ? (I don't remember this behaviour with previous versions of mockgoose)</p></li>
  <li><p>Does mockgoose need this download at each run (npm test) or will the result be reused in the next runs (npm test) ? </p></li>
  <li><p>Can I prevent him to download something. Ideally, I would like to run my unit test in a sandbox env, with no access to the web (in a docker). Can I download the 234mb somewhere and ask mockgoose to reuse it ?</p></li>
  </ul>
  
  <p>Thanks</p>