ViewState seems to work well with the unit testing
framework; though I thought I remembered seeing problems with this in the past,
recent tests show that it does not seem to have the problems that I thought it
did. So the view state may be a safe mechanism to work with. You can reference
the keys and retrieving values from it as you would in any ASP.NET page. The
internal mechanism is a System.Web.UI.StateBag object, and after investigating,
I did not come across anything that may hinder unit testing.