Physics engines in robotics simulators should yield a simulation that is physically faithful to the real world. However, simple scenarios like dropping a ball on the floor already reveal that this is not so. There is hence a need to be able to test such engines in real world scenarios, to see where they are lacking. To help to quickly and efficiently develop unit tests for real-world behavior we developed a tool we call Live Tests for Robotics. In this tool paper we show how its interactive visualizations allow for the efficient construction of such unit tests.