ES6: Convert header view

app/assets/javascripts/discourse/views/header.js.es6

@@ -6,7 +6,7 @@
   @namespace Discourse
   @module Discourse
 **/
-Discourse.HeaderView = Discourse.View.extend({
+export default Discourse.View.extend({
   tagName: 'header',
   classNames: ['d-header', 'clearfix'],
   classNameBindings: ['editingTopic'],

test/javascripts/views/header_view_test.js

@@ -1,10 +1,12 @@
 module("Discourse.HeaderView");
 
+import HeaderView from 'discourse/views/header';
+
 test("showNotifications", function() {
   var controllerSpy = {
     send: sinon.spy()
   };
-  var view = Discourse.HeaderView.create({
+  var view = HeaderView.create({
     controller: controllerSpy
   });