1 files changed, 12 insertions, 0 deletions
diff --git a/devtools/client/styleeditor/test/iframe_service_worker.js b/devtools/client/styleeditor/test/iframe_service_worker.js
new file mode 100644
index 0000000000..56c32c204a
--- /dev/null
+++ b/devtools/client/styleeditor/test/iframe_service_worker.js
@@ -0,0 +1,12 @@
+"use strict";
+
+self.onfetch = function (event) {
+  if (event.request.url.includes("sheet.css")) {
+    return event.respondWith(new Response("* { color: green; }"));
+  }
+  return null;
+};
+
+self.onactivate = function (event) {
+  event.waitUntil(self.clients.claim());
+};