The CallbackWaiter class is a generic async test harness. It can generate handlers on-demand to match the delegates that you need. And it will wait for one of the events to occur or a specified timeout.

The CallbackWaiter can generate mock event handlers which records all the events into a queue for later validation/checking.

Code sample

CallbackWaiter lets you write this kind of code, to test some code involving asynchronous callbacks (such as service.onProgress and service.onComplete).

public void TestFastService()
{
            Service service = new AsyncService(); // your async service which you want to unittest
            
            CallbackWaiter callback = new CallbackWaiter(); 
            service.onProgress += callback.MakeHandler<EventHandler<EventArgs>>("onProgress"); // generate a handler with any type
            service.onComplete += callback.MakeHandler<AnotherDelegateType>("onComplete"); // generate another handler with any type

            service.DoAsyncStuff();

            EventMessage eventMessage = callback.Wait(1000); // wait for a callback or a timeout, whichever comes first

            // The EventMessage has the following information:
            // - is it an event or a timeout (using .IsEvent())
            // - which event was it, in case you wait on multiple events (using .EventName)
            // - what were the arguments of the event (using [0], [1], etc. and casting appropriately)

            Assert.IsTrue(eventMessage.IsEvent());

            Assert.AreEqual("onProgress", eventMessage.EventName);
            Assert.AreEqual(2, eventMessage.Length); 

            Assert.AreEqual(service, (Service)eventMessage[0]);
            Assert.AreEqual(service.eventArgs, (EventArgs)eventMessage[1]);
}

Download

You can browse the code or check it out of SVN.