/**
         * Listens to an event on the given object and returns a reporter function
         * that returns true if the event has been called.
         *
         * @example
         * <p>
         * The following example creates a simple <code>DropDown</code> instance. The dropdown uses event listeners to capture
         * user interaction.
         * </p>
         * <listing>
             var dispatcher:EventDispatcher = new Sprite();
             var spy:Function = TestUtil.spy(dispatcher, Event.OPEN);
             trace(spy()); // false;
             dispatcher.dispatchEvent(Event.OPEN);
             trace(spy()); // true;
         * </listing>
         */
        public static function spyOnEvent(eventTarget : EventDispatcher, eventType : String) : Function
        {
            var didFire : Boolean = false;
            eventTarget.addEventListener( eventType, function(e : Event) : void
            {
                if (e.type == eventType)
                {
                    didFire = true;
                }
            } );

            return function() : Boolean
            {
                return didFire;
            };
        };