This paper presents the approach to functional test automation of services (black-box testing) and service archi-tectures (grey-box testing) that has been developed within the MIDAS project and is accessible on the MIDAS SaaS. In particular , the algorithms and techniques adopted for addressing input and oracle generation, dynamic scheduling, and session planning issues supporting service functional test automation are illustrated. More specifically, the paper details: (i) the test input generation based on formal methods and temporal logic specifications, (ii) the test oracle generation based on service formal specifications, (iii) the dynamic scheduling of test cases based on probabilistic graphical reasoning, and (iv) the reactive, evidence-based planning of test sessions with on the fly generation of new test cases. Finally, the utilisation of the MIDAS prototype for the functional test of operational services and service architectures in the healthcare industry is reported and assessed. A planned evolution of the technology deals with the testing and troubleshooting of distributed systems that integrate connected objects.