diff --git a/tests/helpers/destroy-app.js b/tests/helpers/destroy-app.js
index 5d7454fa17..20b018ecb0 100644
--- a/tests/helpers/destroy-app.js
+++ b/tests/helpers/destroy-app.js
@@ -1,5 +1,10 @@
 import run from 'ember-runloop';
 
 export default function destroyApp(application) {
+    // this is required to fix "second Pretender instance" warnings
+    if (server) {
+        server.shutdown();
+    }
+
     run(application, 'destroy');
 }