diff --git a/client/sw/register.spec.js b/client/sw/register.spec.js
index 259be46a..515a1342 100644
--- a/client/sw/register.spec.js
+++ b/client/sw/register.spec.js
@@ -31,11 +31,13 @@ test('sw: lesten: no sw', (t) => {
     t.end();
 });
 
-test('sw: register: registerSW: no serviceWorker', async (t) => {
+test('sw: register: registerSW: no serviceWorker', async (t, {navigator}) => {
     const {
         registerSW,
     } = reRequire('./register');
     
+    delete navigator.serviceWorker;
+    
     await registerSW();
     
     t.pass('should not call register');