import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

accessible/tests/browser/browser_shutdown_multi_reference.js

@@ -0,0 +1,48 @@
+/* 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/. */
+
+'use strict';
+
+add_task(function* () {
+  info('Creating a service');
+  // Create a11y service.
+  let a11yInit = initPromise();
+  let accService1 = Cc['@mozilla.org/accessibilityService;1'].getService(
+    Ci.nsIAccessibilityService);
+  yield a11yInit;
+  ok(accService1, 'Service initialized');
+
+  // Add another reference to a11y service. This will not trigger
+  // 'a11y-init-or-shutdown' event
+  let accService2 = Cc['@mozilla.org/accessibilityService;1'].getService(
+    Ci.nsIAccessibilityService);
+  ok(accService2, 'Service initialized');
+
+  info('Removing all service references');
+  let canShutdown = false;
+  // This promise will resolve only if canShutdonw flag is set to true. If
+  // 'a11y-init-or-shutdown' event with '0' flag comes before it can be shut
+  // down, the promise will reject.
+  let a11yShutdown = new Promise((resolve, reject) =>
+    shutdownPromise().then(flag => canShutdown ?
+      resolve() : reject('Accessible service was shut down incorrectly')));
+  // Remove first a11y service reference.
+  accService1 = null;
+  ok(!accService1, 'Service is removed');
+  // Force garbage collection that should not trigger shutdown because there is
+  // another reference.
+  forceGC();
+
+  // Have some breathing room when removing a11y service references.
+  yield new Promise(resolve => executeSoon(resolve));
+
+  // Now allow a11y service to shutdown.
+  canShutdown = true;
+  // Remove last a11y service reference.
+  accService2 = null;
+  ok(!accService2, 'Service is removed');
+  // Force garbage collection that should trigger shutdown.
+  forceGC();
+  yield a11yShutdown;
+});