1 files changed, 55 insertions, 0 deletions
diff --git a/js/xpconnect/tests/unit/test_uawidget_scope.js b/js/xpconnect/tests/unit/test_uawidget_scope.js
new file mode 100644
index 0000000000..5d83cdffbb
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_uawidget_scope.js
@@ -0,0 +1,55 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const {NetUtil} = ChromeUtils.importESModule("resource://gre/modules/NetUtil.sys.mjs");
+const {TestUtils} = ChromeUtils.importESModule("resource://testing-common/TestUtils.sys.mjs");
+
+function getWindowlessBrowser(url) {
+  let ssm = Services.scriptSecurityManager;
+  let uri = NetUtil.newURI(url);
+  let principal = ssm.createContentPrincipal(uri, {});
+  let webnav = Services.appShell.createWindowlessBrowser(false);
+
+  let docShell = webnav.docShell;
+  docShell.createAboutBlankDocumentViewer(principal, principal);
+
+  let document = webnav.document;
+  let video = document.createElement("video");
+  document.documentElement.appendChild(video);
+
+  let shadowRoot = video.openOrClosedShadowRoot;
+  ok(shadowRoot, "should have shadowRoot");
+  ok(shadowRoot.isUAWidget(), "ShadowRoot should be a UAWidget");
+  equal(Cu.getGlobalForObject(shadowRoot), Cu.getUAWidgetScope(principal),
+        "shadowRoot should be in UAWidget scope");
+
+  return webnav;
+}
+
+function StubPolicy(id) {
+  return new WebExtensionPolicy({
+    id,
+    mozExtensionHostname: id,
+    baseURL: `file:///{id}`,
+    allowedOrigins: new MatchPatternSet([]),
+    localizeCallback(string) {},
+  });
+}
+
+// See https://bugzilla.mozilla.org/show_bug.cgi?id=1588356
+add_task(async function() {
+  let policy = StubPolicy("foo");
+  policy.active = true;
+
+  let webnav = getWindowlessBrowser("moz-extension://foo/a.html");
+  webnav.close();
+
+  // Wrappers are nuked asynchronously, so wait for that to happen.
+  await TestUtils.topicObserved("inner-window-nuked");
+
+  webnav = getWindowlessBrowser("moz-extension://foo/a.html");
+  webnav.close();
+
+  policy.active = false;
+});