Sigh.  Can you at least see how a subject of "Assertion fails" and  
comments in your original post like "my assertions...fail in every case"  
were counter-productive with respect to describing your problem?

What do you mean "normally"?  In what situation do you not have to handle  
the exception yourself?

It certainly could be.  It depends on how the event handler is being  
executed.

Presumably there's some aspect about the question that is specific to this  
"test for a workflow", and since I'm not familiar with the use of  
"workflow" in the context of .NET, I don't fully understand the question.

Frankly, at this point I would recommend that you start a whole new  
thread, and put a subject that actually describes what the issue is,  
including the specific area of .NET in which you're working (i.e. assuming  
"workflow" has a specific meaning here, be very specific in your subject  
about the fact that you're using this "workflow", and make sure you use  
the precise terminology/type/etc. that .NET would use).

As things stand now, the few people who might understand the context of  
"workflow" may well have just skipped past the thread, because there's  
nothing immediately visible in the thread that would alert them to the  
fact that it's something they might know something about.

Finally, given the apparent esoteric nature of the question, you should  
probably post a concise-but-complete code sample that reliably  
demonstrates the problem.  The sample should demonstrate both the case  
that works as you expect, as well as the case that doesn't.

Pete