1 files changed, 16 insertions, 0 deletions
diff --git a/testing/web-platform/tests/html/browsers/browsing-the-web/back-forward-cache/resources/echo-worker.js b/testing/web-platform/tests/html/browsers/browsing-the-web/back-forward-cache/resources/echo-worker.js
new file mode 100644
index 0000000000..3e3ecb52e9
--- /dev/null
+++ b/testing/web-platform/tests/html/browsers/browsing-the-web/back-forward-cache/resources/echo-worker.js
@@ -0,0 +1,16 @@
+// On receiving a message from the parent Document, send back a message to the
+// parent Document. This is used to wait for worker initialization and test
+// that this worker is alive and working.
+
+// For dedicated workers.
+self.addEventListener('message', event => {
+  postMessage(event.data);
+});
+
+// For shared workers.
+onconnect = e => {
+  const port = e.ports[0];
+  port.onmessage = event => {
+    port.postMessage(event.data);
+  }
+};