Tests: Object.prototype.toLocaleString(). Related bug: 3989 JSC doesn't implement Object.prototype.toLocaleString() On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS o.toLocaleString() is o.toString() PASS o.toLocaleString() is "Dynamic toLocaleString()" PASS successfullyParsed is true TEST COMPLETE