Use ES6 import in CodeManager tests

test/specs/code_manager/index.js

@@ -1,5 +1,5 @@
-var CodeManager = require('code_manager');
-var Models = require('./model/CodeModels');
+import CodeManager from 'code_manager';
+import Models from './model/CodeModels';
 
 describe('Code Manager', () => {
   describe('Main', () => {

test/specs/code_manager/model/CodeModels.js

@@ -1,9 +1,9 @@
-const CssGenerator = require('code_manager/model/CssGenerator');
-const HtmlGenerator = require('code_manager/model/HtmlGenerator');
-const DomComponents = require('dom_components');
-const Component = require('dom_components/model/Component');
-const Editor = require('editor/model/Editor');
-const CssComposer = require('css_composer');
+import CssGenerator from 'code_manager/model/CssGenerator';
+import HtmlGenerator from 'code_manager/model/HtmlGenerator';
+import DomComponents from 'dom_components';
+import Component from 'dom_components/model/Component';
+import Editor from 'editor/model/Editor';
+import CssComposer from 'css_composer';
 
 module.exports = {
   run() {