diff --git a/blueprints/app/files/tests/helpers/start-app.js b/blueprints/app/files/tests/helpers/start-app.js
index 54c33c16cb..e098f1d5be 100644
--- a/blueprints/app/files/tests/helpers/start-app.js
+++ b/blueprints/app/files/tests/helpers/start-app.js
@@ -5,8 +5,8 @@ import config from '../../config/environment';
 export default function startApp(attrs) {
   let application;
 
-  // use defaults, but you can override
-  let attributes = Ember.assign({}, config.APP, attrs);
+  let attributes = Ember.merge({}, config.APP);
+  attributes = Ember.merge(attributes, attrs); // use defaults, but you can override;
 
   Ember.run(() => {
     application = Application.create(attributes);