1 files changed, 41 insertions, 0 deletions
diff --git a/toolkit/components/aboutperformance/tests/browser/workers.html b/toolkit/components/aboutperformance/tests/browser/workers.html
new file mode 100644
index 0000000000..29bb895ae2
--- /dev/null
+++ b/toolkit/components/aboutperformance/tests/browser/workers.html
@@ -0,0 +1,41 @@
+<!DOCTYPE html>
+<html>
+<head>
+  <meta charset="UTF-8">
+  <title>
+    Main frame for test browser_aboutperformance.js
+  </title>
+</head>
+<body>
+
+<p>
+fib(<span id="n">?</span>) = <span id="result">?</span>
+</p>
+
+</body>
+<script>
+  var result = document.querySelector('#result');
+  var span_n = document.querySelector('#n');
+  var worker = new Worker("workers_script.js");
+  var n = 1;
+
+  var wait = new Promise(ready => {
+    worker.onmessage = function(event) {
+      result.textContent = event.data;
+      span_n.textContent = n;
+      console.log(`Got: fib($n) = $result\n`);
+      n++;
+      ready();
+      // Keep looping to keep the worker as "High energy use"
+      worker.postMessage(n);
+    };
+  });
+
+  worker.postMessage(n);
+
+  window.waitForTestReady = async () => {
+    await wait;
+  };
+
+</script>
+</html>