Wireless sensor networks (WSNs) are being increasingly introduced for critical applications such as safety, security and health. One the main characteristic requirements of such networks are that they should function with relative low power. Therefore the wireless links are more vulnerable. Successfully testing wireless coexistence and potential vulnerabilities of such networks against interference is of crucial importance. Reverberation chambers represent a successful environment for various tests regarding performance evaluation of wireless communication systems. In this study, the authors propose a test methodology specifically developed for assessing WSNs performance under different channel and interference conditions.