The $.getScript() method doesn't have an error callback function; if your problem is that you doesn't get the script, the callback function of $.getScript would never be called than you should use the $.ajax method intead as shown ahead:

  $.ajax({
      type: "GET",
      url: "test.js",
      dataType: "script"
      error: function (XMLHttpRequest, textStatus, errorThrown) {},
      success:function(){ [function to call] }
   });

Otherwise if you have errors once the callback is called (and that means the script is on the page) than you should manage the error in your callback function.