Fixed tests

src/css_composer/model/CssRule.js

@@ -4,6 +4,8 @@ import Styleable from 'domain_abstract/model/Styleable';
 import { isEmpty, forEach } from 'underscore';
 import Selectors from 'selector_manager/model/Selectors';
 
+const { CSS } = window;
+
 export default Backbone.Model.extend(Styleable).extend({
   defaults: {
     // Css selectors

src/style_manager/view/LayerView.js

@@ -32,7 +32,7 @@ export default Backbone.View.extend({
 
   initialize(o = {}) {
     let model = this.model;
-    this.stackModel = o.stackModel || {};
+    this.stackModel = o.stackModel;
     this.config = o.config || {};
     this.em = this.config.em;
     this.pfx = this.config.stylePrefix || '';