Recently, XMPP protocol is gaining momentum in Internet of things (IoT). It has been widely used in chatting, message exchanging, unique addressing, etc. which raises an interesting issue: How to formally test the conformance and performance of XMPP in IoT environment. While conformance testing of communicating protocols is a functional test which verifies whether the behaviors of the protocol satisfy defined requirements, performance testing is a qualitative and quantitative test which aims at checking whether the performance requirements of the protocol are satisfied under certain conditions. In this paper, we present a logic-based approach to test the conformance and performance of XMPP protocol through real execution traces and formally specified properties. In order to evaluate and assess our methodology, we have developed a prototype and present experiments with a set of XMPP properties. Finally, the relevant verdicts and conclusions are provided