fix ember-cli-fastboot-testing-app test

Author: Gaurav0

test-packages/ember-cli-fastboot-testing-app/tests/index.html

@@ -21,6 +21,9 @@
     {{content-for "body"}}
     {{content-for "test-body"}}
 
+    <div id="ember-testing">
+    </div>
+
     <script src="/testem.js" integrity=""></script>
     <script src="{{rootURL}}assets/vendor.js"></script>
     <script src="{{rootURL}}assets/test-support.js"></script>

test-packages/ember-cli-fastboot-testing-app/tests/test-helper.js

@@ -2,6 +2,10 @@ import Application from '../app';
 import config from '../config/environment';
 import { setApplication } from '@ember/test-helpers';
 import { start } from 'ember-qunit';
+import * as QUnit from 'qunit';
+import { setup } from 'qunit-dom';
+
+setup(QUnit.assert);
 
 setApplication(Application.create(config.APP));