Make sure you are loading those modules (myApp.services and myApp.directives) as dependencies of your main app module, like this:
angular.module('myApp', ['myApp.directives', 'myApp.services']);
plunker: http://plnkr.co/edit/wxuFx6qOMfbuwPq1HqeM?p=preview
~ Answered on 2013-03-06 11:43:05