Brandon Savage has a quick post to his site sharing some advice around the testing of your application, more specifically around unit tests: don't write useless unit tests. He starts with an example of a test that, while moving the project closer to the 100% coverage number, is mostly useless.

Too often, in the search for 100% unit test code coverage, I see tests like this get written. They don’t serve a practical purpose, except to meet the test coverage goal. Worse, they don’t actually improve the quality of the application.

Instead of writing a unit test here, we would be better served by writing an integration test, or a functional test. These tests would require us to interact directly with the database, but would provide far more valuable information about the health and status of our application. A useless unit test provides us with little if any benefit; a useful functional test provides us with tremendous advantages.

He includes the code for the test and talks about what's wrong with the approach and how it could potentially be handled better. He suggests that writing good, useful tests requires both skill and determination and the avoidance of tests that actually increase the quality of the overall test suite.