Unit test a customized application block.
Integration test a customized application block.
Microsoft application blocks are designed, developed, and tested extensively so that they can be integrated with your applications in an off-the-shelf manner, without any further modification or testing. If you need to modify or extend the existing functionality to suit your application requirements, you may need to unit test the application block before integrating it with your application. There are several benefits to customizing an application block, including the following:
You can add functionality to the application block so that it is able to fulfill application-specific needs. ...