Microsoft Visual Studio 2015 Unleashed, Third Edition

Testing Your Exceptions

You should write unit tests to verify your code behaves as expected in both positive and negative conditions. The positive conditions can be verified using the Assert methods, as discussed previously. However, many times you want to verify that your code returns the correct exception when you call or use it in a certain manner. In this case, you can decorate a test method with the ExpectedException attribute to test for specific error conditions.

The attribute takes the type of expected exception as a parameter. If the test method results in an exception being thrown and the type of that exception is as you defined in the attribute, the test is considered a success. If an exception is not thrown or an exception of a different ...