This tests that Symbol.prototype object is ordinary object (not Symbol wrapper object). On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS Symbol.prototype.toString.call(Symbol.prototype) threw exception TypeError: Symbol.prototype.toString requires that |this| be a symbol or a symbol object. PASS Symbol.prototype.toString.call(Symbol.iterator) is "Symbol(Symbol.iterator)" PASS successfullyParsed is true TEST COMPLETE