diff --git a/addons/web_tests_demo/static/src/js/demo.js b/addons/web_tests_demo/static/src/js/demo.js
index b35b44b80f8..506808027cc 100644
--- a/addons/web_tests_demo/static/src/js/demo.js
+++ b/addons/web_tests_demo/static/src/js/demo.js
@@ -1,11 +1,11 @@
 // static/src/js/demo.js
 openerp.web_tests_demo = function (instance) {
-    instance.web_tests_demo = {
+    _.extend(instance.web_tests_demo, {
         value_true: true,
         SomeType: instance.web.Class.extend({
             init: function (value) {
                 this.value = value;
             }
         })
-    };
+    });
 };