Event Driven Programming: A sequence of unfortunate events

Question

I have a very basic game loop whose primary purpose is to check for updates & changes to a list.

I have contemplated using event driven programming to replace the game loop/list idea with an ObservableCollection, however I just have this big cloud of doubt on event driven programming. I'm posing these questions to those with experience with event driven programming:

1. What are good ways to test & build an event driven programming design?

   That is, how will I know that I cannot run into "a sequence of unfortunate events"? I want to avoid the events I didn't plan for.

2. Are there unit tests schemes to test event driven programming?

Observable collections are found at:

http://msdn.microsoft.com/en-us/library/ms668604.aspx