QTronic is a leading provider of tools for virtual validation of automotive functions. With the help of Silver, our virtual ECU platform, accurate executable models of the car ECUs can be built. This way, virtual test drives can be performed on PCs with realistic models of the car control software. Even with good simulation models, huge numbers of scenarios and parameter variations must be considered and safe-guarded before releasing automated driving functions. Our tool TestWeaver helps investigate the behavior of the simulated system in large parameter spaces. Classical test automation is complemented by thousands of computer-generated scenario variations guided by intelligent search algorithms - in order to increase the test coverage and in order to identity the critical situations.