A composite system consists of several components which can be developed separately and deployed in distributed environments. Executing test cases on such kind of systems requires more effort due to their size and their distributed environments. A critical issue is to prioritize efficient test cases to be firstly executed. We present in this paper a framework to generate test cases and to select the efficient ones to test the composite systems with taking into account time properties. Particularly, the framework generates a set of test cases based on a model of the system, which cover a given test objective. The test cases are then prioritized in an execution order to detect quickly faults, thus reducing the efforts of test execution and increasing the effectiveness of the testing process. The framework is complemented with an open-source toolchain for automating test case generation. It has been experimentally evaluated on the European Train Control System case study. The initial results show that the approach can save 40% of test execution effort