This tutorial shows how BDD can be done from early requirement collection stage to late integration tests. It explains breaking user stories into behaviors, and then developers and test engineers taking the behavior specs and writing a WCF service and unit test for it, in parallel, and then eventually integrating the WCF service and doing the integration tests. It introduces how mocking is done using the Moq library. Moreover, it shows a way how you can write test once and do both unit and integration tests at the flip of a configuration setting.