With more and more manufacturers positioning their electric vehicles on the market, the necessity for ensuring European-wide interoperability of charging infrastructure and electric vehicles becomes eminent. While standards are in place to guarantee compatibility, testing of function-level interoperability is still an open issue. Besides already widely performed testing of single charging stations, the evaluation of a heterogeneous compounds of charging infrastructure and thereby caused mutual influence is highly relevant. To allow for such challenging, big scale evaluation that also involves real charging infrastructure, co-simulation with hardware integration is the way to go. This paper deals with an appropriate architecture and set-up of such a co-simulation framework that can be used to generate test vectors on communication and power interfaces to test charging stations and electric vehicle charging interfaces. The effectiveness of the tool-set is validated with a case study demonstrating a distributed charging management algorithm operating on charging stations connected via the Open Charge Point Protocol (OCPP).