how to make testing possible of sandboxed api #2

sandboxtesting2.js

(function () {  

    var PublicAPI = window.PublicAPI = {};        
    PublicAPI.publicFunction = function (foo) {
        PrivateAPI.privateFunction(foo);
        return 'bar';
    };

    var PrivateAPI = {};
    PrivateAPI.privateFunction = function (foo) {
       // Make secret stuff that never gets returned to the public
       // Could be an XHR call.
    };

    // Assign PrivateAPI to window in order to perform unit testing of PrivateAPI.
    // Remove this in production
    window.PrivateAPI = PrivateAPI;

})();