But, let’s be pragmatic for a second, the 80/20 rule states that you get 80% of the value from 20% of the work and a couple of simple tests are vastly better than no tests at all. Start small and simple, make sure you get something out of the testing first, then expand the test suite and add more complexity until you feel that you’ve reached the point where more effort spent on realism will not give enough return on your invested time.