diff -r 000000000000 -r 6474c204b198 toolkit/mozapps/extensions/test/xpcshell/test_bug616841.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/mozapps/extensions/test/xpcshell/test_bug616841.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,26 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+// Tests that string comparisons work correctly in callbacks
+
+function test_string_compare() {
+  do_check_true("C".localeCompare("D") < 0);
+  do_check_true("D".localeCompare("C") > 0);
+  do_check_true("\u010C".localeCompare("D") < 0);
+  do_check_true("D".localeCompare("\u010C") > 0);
+}
+
+function run_test() {
+  createAppInfo("xpcshell@tests.mozilla.org", "XPCShell", "1", "1.9.2");
+  startupManager();
+
+  do_test_pending();
+
+  test_string_compare();
+
+  AddonManager.getAddonByID("foo", function(aAddon) {
+    test_string_compare();
+    do_execute_soon(do_test_finished);
+  });
+}