var Test = function(Foo) {
    function Test() {
        Foo.prototype.test;
        Foo.prototype.test.whatever;
    }

    Test.prototype = Object.create(Foo.prototype, {
        constructor: {
            value: Test,
            enumerable: false,
            writable: true,
            configurable: true
        }
    });

    Test.__proto__ = Foo;
    return Test;
}(Foo);