michael@0: const Cu = Components.utils;
michael@0: 
michael@0: function run_test() {
michael@0:   var sb = new Cu.Sandbox('http://www.example.com');
michael@0:   sb.arr = [3, 4];
michael@0:   do_check_true(Cu.evalInSandbox('Array.isArray(arr);', sb));
michael@0: }