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); }