Complex and distributed nature of multi-agent systems (MASs) makes it almost impossible to identify of all requirements at the beginning of the development. Hence, development of such systems needs an iterative and incremental process to handle complexity and the continuously changing na-ture of the requirements. In this paper, a test driven multi-agent system devel-opment approach that naturally supports iterative and incremental MAS con-struction is proposed. Also a testing framework called as SUnit which supports the proposed approach by extending JUnit framework is introduced. This framework allows writing automated tests for agent behaviors and interactions between agents. The framework also includes the necessary mock agents to model the organizational aspects of the MAS.