Testing Async service that uses callbacks, not Events

Question

Hello All,
I am curios how others are writing Async tests on a service layer where events are not used?
Ex: calling into a service object - sending a callback method (closure)
private function buyItem(id:String, callback:Function
DataManager.getInstance().purchaseItem(id, callback);
private function callback(success:Boolean, data:Object):void
     // Do stuff
TestBuyItem.as
[Test (order=1, async, timeout="60000")]
public function testBuyItem():void
     Async.asyncHandler(this, callback, 20000, null, null);
     DataManager.getInstance().purchaseItem("myitemid", callback);
private function callback(success:Boolean, data:Object
     // This method gets called and success does equal true - however my test fails
     Assert.assertTrue(success);
What am I doing wrong? 
What type of method does the 'callback' need to be?
Is there an Async.waitForCallbackFunctionCall()
I am sure I am doing something wrong, I am just not sure what - thanks for any help you can offer.
--jason

Answer 1

Jason,
Async.asyncHandler(... returns a function. This is your callback. Store a reference to it, and when you receive the result in your callback, execute the function that was returned from Async.asyncHandler.
The asyncHandler signature is "handler(event:Event, passThroughData:Object):void". Just create a dummy event that wraps the data from your callback and invoke the handler.
Hope this helps,
Russ