Use-cases and scenarios have been identified as good inputs to generate test cases and oracles at requirement level. Yet to have an automated generation, information is missing from use cases and sequence diagrams, such as the exact inputs of the system, and the ordering constraints between the use case. The contribution of this paper is then two-fold. First we propose a contract language for functional requirements expressed as parameterized use cases. Then we provide a method, a formal model and a prototype tool to automatically derive both functional and robustness test cases from the requirements enhanced with contracts. We study the efficiency of the generated test cases on a case study.