The paper presents mathematical and implementation challenges associated with testing of embedded software systems with dynamic behavior. These challenges are related to notation of tests, calculation of test coverage, implementation of a test comparator, and automatic generation of test cases. Some author’s ideas and solutions are presented with the help of abstract models that describe behavior of the software systems. The models are represented using the state space (or input/state/output) notation. An application example is given to illustrate theoretical analysis and mathematical formulation.