Abstract-There are numerous methods which are proposed to mediate semantic Web services. The mediations of semantic services include their discovery, composition, execution, and monitoring. These are performed on both atomic and composite services. Newly proposed methods are required to be evaluated on a dataset. Despite the existence of atomic test collections of semantic services, the number of publicly available test collections containing composite services is not comparable. In this paper, we propose an approach to enlarge the number of composite services in a test collection. We generate new composites by calculating subdigraphs of available composite services. We evaluated our approach on a number of composite services and we could exponentially enlarge the size of test collections.