diff -r 000000000000 -r 6474c204b198 services/sync/tests/unit/test_utils_getErrorString.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/services/sync/tests/unit/test_utils_getErrorString.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,14 @@
+Cu.import("resource://services-sync/util.js");
+
+function run_test() {
+  let str;
+
+  // we just test whether the returned string includes the
+  // string "unknown", should be good enough
+
+  str = Utils.getErrorString("error.login.reason.account");
+  do_check_true(str.match(/unknown/i) == null);
+
+  str = Utils.getErrorString("foobar");
+  do_check_true(str.match(/unknown/i) != null);
+}