text: var assert = chai.assert;
  
  describe('addClass', function() {
    it('should add class to element', function() {
      var element = { className: '' };
  
      addClass(element, 'test-class');
  
      assert.equal(element.className, 'test-class');
    });
  
    it('should not add a class which already exists', function () {
      var element = { className: 'exists' };
      addClass(element, 'exists');
  
      var numClasses = element.className.split(' ').length;
      assert.equal(numClasses, 1);
    });
  
    it('should append new class after existing one', function () {
      var element = { className: 'exists' };
  
      addClass(element, 'new-class');
  
      var classes = element.className.split(' ');
      assert.equal(classes[1], 'new-class');
    });
  });
  
  // var expect = require('chai').expect;
  
  // describe('A basic test', function () {
  //     it('should pass when everything is ok', function () {
  //         expect(true).to.be.true;
  //     });
  // });