  Currently, practitioners follow a top-down approach in automotive development
projects. However, recent studies have shown that this top-down approach is not
suitable for the implementation and testing of modern automotive systems.
Specifically, practitioners increasingly fail to specify requirements and tests
for systems with complex component interactions (e.g., e-mobility systems). In
this paper, we address this research gap and propose an integrated and
iterative scenario-based technique for the specification of requirements and
test scenarios. Our idea is to combine both a top-down and a bottom-up
integration strategy. For the top-down approach, we use a behavior-driven
development (BDD) technique to drive the modeling of high-level system
interactions from the user's perspective. For the bottom-up approach, we
discovered that natural language processing (NLP) techniques are suited to make
textual specifications of existing components accessible to our technique. To
integrate both directions, we support the joint execution and automated
analysis of system-level interactions and component-level behavior. We
demonstrate the feasibility of our approach by conducting a case study at
Kostal (Tier1 supplier). The case study corroborates, among other things, that
our approach supports practitioners in improving requirements and test
specifications for integrated system behavior.
