Test Script for Event driven function

Yes.

At the simplest, you could have a test like this:

[Test]

public function shouldThrowEvent():void {

  var eventCalled:Boolean = false;

  var someEventDispatcher:SomeEventDispatcher = new SomeEventDispatcher();

  someEventDispatcher.addEventListener( "someEvent",

          function ( event:Event ) {

               eventCalled = true;

          }

  assertTrue( eventCalled );

}

I would recommend looking at docs.flexunit.org for more information.

Mike