How to test ExpressJS route and "controller" separately

I have an Express route defined like this (where app

is my Express app):

module.exports = function(app) {
  var controller = require('../../app/controllers/experiment-schema');
  app.route('/api/experiment-schemas/random').get(controller.random);
};

      

        
        
        
      

    

In this "controller" file, I have this method:

exports.random = function (req, res, callback) {

  ExperimentSchema.count({}, function (err, count) {

    var rand = Math.floor(Math.random() * count);

    ExperimentSchema.find({})
      .skip(rand)
      .limit(1)
      .populate('mediaPool', 'artist title label')
      .exec(function (err, schema) {

        res.json(200, schema);

        if (typeof callback === 'function') {
          callback();
        }
      });
  });
}

      

        
        
        
      

    

Here ExperimentSchema

is Mongoose model. Since the controller method hits the database, I pass a callback in my test so that I can wait for these requests to return to the database and check the return value. I am doing this based on this question .

When I go to test a route, I test supertest

by actually making an HTTP call to the route. The problem is that when I do this, Express injects next

as the third argument into my method random

. Now, callback()

aliases next()

, and things go hard. How can I check my route and my controller separately?