Abstract: It has been more than seven years since the first release of NUnit 2.0, an open source unit testing tool. In that time, literally millions of tests have been written using the tool. Many of these tests have become and continue to be invaluable resources for their teams. Unfortunately, many other NUnit-based tests have not been maintained and are now viewed as having been a waste of effort from the beginning. What separates tests that are used, maintained, and highly valued from tests that are quickly discarded? This session describes seven key ideas that will increase the readability of NUnit tests and make them much easier to maintain. Learn about the impact of test fixture size, dependency injection, and mock frameworks on unit testing. Other lessons include information on usage of [ExpectedException], [Setup], and [TearDown]. Incorporating these and the other lessons can make the difference between tests that become a burden to the team and tests that become practical, growing resources.