3 files changed, 57 insertions, 0 deletions
diff --git a/dom/locks/test/file_strongworker.js b/dom/locks/test/file_strongworker.js
new file mode 100644
index 0000000000..36871ad31a
--- /dev/null
+++ b/dom/locks/test/file_strongworker.js
@@ -0,0 +1,5 @@
+navigator.locks.request("exclusive", () => {
+  const channel = new BroadcastChannel("strongworker");
+  channel.postMessage("lock acquired");
+});
+postMessage("onload");
diff --git a/dom/locks/test/mochitest.ini b/dom/locks/test/mochitest.ini
new file mode 100644
index 0000000000..48a8d7df1d
--- /dev/null
+++ b/dom/locks/test/mochitest.ini
@@ -0,0 +1,8 @@
+[DEFAULT]
+scheme = https
+prefs =
+  dom.weblocks.enabled=true
+
+[test_strongworker.html]
+support-files =
+  file_strongworker.js
diff --git a/dom/locks/test/test_strongworker.html b/dom/locks/test/test_strongworker.html
new file mode 100644
index 0000000000..9c6905919c
--- /dev/null
+++ b/dom/locks/test/test_strongworker.html
@@ -0,0 +1,44 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<script src="/tests/SimpleTest/SimpleTest.js"></script>
+<link rel="stylesheet" href="/tests/SimpleTest/test.css"/>
+
+<script>
+  SimpleTest.waitForExplicitFinish();
+
+  async function run() {
+    // Bug 1746646: Make mochitests work with TCP enabled (cookieBehavior = 5)
+    // Acquire storage access permission here so that the BroadcastChannel used to
+    // communicate with the opened windows works in xorigin tests. Otherwise,
+    // the iframe containing this page is isolated from first-party storage access,
+    // which isolates BroadcastChannel communication.
+    if (isXOrigin) {
+      SpecialPowers.wrap(document).notifyUserGestureActivation();
+      await SpecialPowers.addPermission(
+        "storageAccessAPI",
+        true,
+        window.location.href
+       );
+      await SpecialPowers.wrap(document).requestStorageAccess();
+    }
+    const channel = new BroadcastChannel("strongworker");
+    await navigator.locks.request("exclusive", async () => {
+      await new Promise(resolve => {
+        let worker = new Worker("./file_strongworker.js");
+        worker.onmessage = resolve; // onload
+      });
+      const query = await navigator.locks.query();
+      is(query.pending.length, 1, "Pending request exists");
+
+      // Garbage collect the worker
+      SpecialPowers.DOMWindowUtils.garbageCollect();
+    });
+
+    channel.onmessage = async event => {
+      const query = await navigator.locks.query();
+      is(query.pending.length, 0, "No pending request");
+      SimpleTest.finish();
+    };
+  }
+  run();
+</script>