Unit tests are an essential part of any test suite. Written by developers for developers, they test the code at the lowest level. While unit tests are great for verifying individual components, they may not reflect the system's behavior in real-world scenarios. Above all, unit tests cannot ensure that the correct feature has been implemented or that a feature has been implemented correctly. This is where acceptance tests come into play, designed from the user's perspective to ensure the system meets their requirements and expectations. Positioned one level above unit tests in the testing pyramid, acceptance tests can be written by non-developers in a formal, natural language, describing specific examples of use cases. With the appropriate tools, these can be made automatically executable, resulting in an executable specification and rendering manual regression tests a thing of the past. This approach, also called Behaviour-Driven Development (BDD), facilitates a shared understanding of requirements through a common language, bridging the gap between technical and non-technical team members. Additionally, a living documentation can be generated, which makes it clear for everyone at any time which features have already been implemented and are working and what has not yet been implemented or does not work.

In this talk, we will explore the basics of BDD and acceptance tests. Then, using a concrete example, we will demonstrate how acceptance tests can be implemented in .NET with SpecFlow, providing attendees with actionable knowledge on integrating these practices into their projects.