old_contents: var expect = require("chai").expect;
  
  var copyrightHelper = require('../helpers/modules/copyright');
  
  describe('copyright', function() {
  
      'use strict';
  
      describe('Arguments validation', function() {
  
          it('should throw TypeError if startYear argument is not an integer', function() {
              var err = new TypeError('startYear must be an integer');
              expect(copyrightHelper.getCopyright.bind('2019', 2023)).to.throw(TypeError);
          });
  
          it('should throw TypeError if currentYear argument is not an integer', function() {
              var err = new TypeError('currentYear must be an integer');
              expect(copyrightHelper.getCopyright.bind(2017, '2019')).to.throw(TypeError);
          });
  
          it('should throw RangeError if currentYear argument is less than startYear', function() {
              var err = new TypeError('startYear must be equal to or less than currentYear');
              expect(copyrightHelper.getCopyright.bind(2020, 2028)).to.throw(TypeError);
          });
  
      });
  
      describe('Return values', function() {
  
          it('should return correct text if startYear is equal to currentYear', function() {
              var startYear = 2018,
                  currentYear = 2018,
                  text = `${currentYear}`;
  
              var copyright = copyrightHelper.getCopyright(startYear, currentYear);
  
              expect(copyright).to.equal(text);
          });
  
          it('should return correct text if startYear is less than currentYear', function() {
              var startYear = 2014,
                  currentYear = 2020,
                  text = `${startYear} - ${currentYear}`;
  
              var copyright = copyrightHelper.getCopyright(startYear, currentYear);
  
              expect(copyright).to.equal(text);
          });
  
      });
  
  });
new_contents: var expect = require("chai").expect;
  
  var copyrightHelper = require('../helpers/modules/copyright');
  
  describe('copyright', function() {
  
      'use strict';
  
      describe('Arguments validation', function() {
  
          it('should throw TypeError if startYear argument is not an integer', function() {
              var fn = function(){
                  copyrightHelper.getCopyright('2019', 2023);
              };
  
              expect(fn).to.throw(TypeError, 'startYear must be an integer');
          });
  
          it('should throw TypeError if currentYear argument is not an integer', function() {
              var fn = function(){
                  copyrightHelper.getCopyright(2017, '2019');
              };
  
              expect(fn).to.throw(TypeError, 'currentYear must be an integer');
          });
  
          it('should throw RangeError if currentYear argument is less than startYear', function() {
              var fn = function(){
                  copyrightHelper.getCopyright(2028, 2020);
              };
  
              expect(fn).to.throw(RangeError, 'startYear must be equal to or less than currentYear');
  
          });
  
      });
  
      describe('Return values', function() {
  
          it('should return correct text if startYear is equal to currentYear', function() {
              var startYear = 2018,
                  currentYear = 2018,
                  text = `${currentYear}`;
  
              var copyright = copyrightHelper.getCopyright(startYear, currentYear);
  
              expect(copyright).to.equal(text);
          });
  
          it('should return correct text if startYear is less than currentYear', function() {
              var startYear = 2014,
                  currentYear = 2020,
                  text = `${startYear} - ${currentYear}`;
  
              var copyright = copyrightHelper.getCopyright(startYear, currentYear);
  
              expect(copyright).to.equal(text);
          });
  
      });
  
  });
subject: Fix copyright module tests