Service-oriented architectures and web services have been used as important technologies to foster the development of loosely coupled and distributed applications. Web services pose new challenges for the testing activity, mainly because mission-critical and complex business process systems are implemented with them. In this context, formal testing approaches are necessary to guarantee the service quality. In this document, we identify formal approaches proposed to test service-oriented architectures and web services, analyzing the application context, models, empirical study, authorship, and references. A systematic review was planned and executed to select the studies considered in this work. We observed that, though more experiments and cooperation are necessary, there is a considerable interest in the topic.