Test events with nunit

Question

I'm just starting with TDD and could solve most of the problems I've faced on my own. But now I'm lost: How can I check if events are fired? I was looking for something like Assert.Raise or Assert.Fire but there's nothing. Google was not very useful, most of the hits were suggestions like foo.myEvent += new EventHandler(bar); Assert.NotNull(foo.myEvent); but that proves nothing.

Thank you!

Answer 1

Checking if events were fired can be done by subscribing to that event and setting a boolean value:

var wasCalled = false; foo.NyEvent += (o,e) => wasCalled = true;  ...  Assert.IsTrue(wasCalled); 

Due to request - without lambdas:

var wasCalled = false; foo.NyEvent += delegate(o,e){ wasCalled = true;}  ...  Assert.IsTrue(wasCalled); 

Answer 2

I prefer to do as follows:

var wait = new AutoResetEvent(false); foo.MeEvent += (sender, eventArgs) => { wait.Set(); }; Assert.IsTrue(wait.WaitOne(TimeSpan.FromSeconds(5))); 

Advantages: Supports multithreading scenario (if handler is invoked in different thread)