Congestion in the RF spectrum is rapidly increasing, which has motivated the need for efficient spectrum sharing techniques. A cognitive radar system has been developed to implement a perception action cycle, for spectrum sharing, in which the RF spectrum is sensed, other RF signals are identified, and the radar frequency band of operation is adapted to avoid interfering signals in the spectrum. The system operates in real time and is capable of coexisting with common communications signals. A system with this capability requires efficient programming that pushes the limits of the technology available. In order to properly test the performance of a radar system designed for this kind of reactive spectrum sharing, a rigorous set of synthetic interference signals is generated and several informative evaluation metrics are defined. Additionally, the system's performance is evaluated with common communications signals such as LTE and GSM. The performance of the system is found to be adequate for avoiding signals that are either varying in frequency or turning on and off at rates on the order of 10 ms.