How to use the supertest/lib/test.prototype function in supertest

'use strict';

import Promise from 'bluebird';
import Test from 'supertest/lib/test';
Test.prototype.end = Promise.promisify(Test.prototype.end);

import supertest from 'supertest';

import Koa from 'koa';
import AuthX, { EmailStrategy, GoogleStrategy, PasswordStrategy, SecretStrategy, InContactStrategy } from '../../src/index.js';


module.exports = {
	setup: function(done){
		global.authx = new AuthX(global.setup.config, {
			email: EmailStrategy,
			google: GoogleStrategy,
			password: PasswordStrategy,
			secret: SecretStrategy,
			incontact: InContactStrategy
		});

var supertest = require('supertest');
var config = require('./config');

var Test = require('supertest/lib/test');

originalAssert = Test.prototype.assert;
Test.prototype.assert = function kongaAssert(resError, res, fn){
  if (!res && resError) return fn.call(this, resError);
  return originalAssert.call(this, resError, res, fn);
};

var client = supertest(config.kong_url);
module.exports = client;

var supertest = require('supertest');
var config = require('./config');

var Test = require('supertest/lib/test');

originalAssert = Test.prototype.assert;
Test.prototype.assert = function kongaAssert(resError, res, fn){
  if (!res && resError) return fn.call(this, resError);
  return originalAssert.call(this, resError, res, fn);
};

var client = supertest(config.kong_url);
module.exports = client;