function test() {

function * generatorFn(){}
var ownProto = Object.getPrototypeOf(generatorFn());
var passed = ownProto === generatorFn.prototype;

var sharedProto = Object.getPrototypeOf(ownProto);
passed &= sharedProto !== Object.prototype &&
  sharedProto === Object.getPrototypeOf(function*(){}.prototype) &&
  sharedProto.hasOwnProperty('next');

return passed;
      
}

if (!test())
    throw new Error("Test failed");