According to the principles of Behavior Driven Development (BDD), we discuss examples and write them down as Gherkin scenarios. These scenarios can be turned into automated tests by BDD tools like Cucumber or SpecFlow, so that the implementation can be “driven” by them. So it is like TDD. But if it is like TDD, there arises the question whether we also need unit tests and classic unit-level-TDD as well in addition to our scenarios. This is a complex question and it is not easy to give a simple constructive answer for it. In this post, I am taking a concrete example to show how this can be imagined.