In this paper, we consider typical applications in which the business logic is separated from the access control logic, implemented in an independent component, called the Policy Decision Point (PDP). The execution of functions in the business logic should thus include calls to the PDP, which grants or denies the access to the protected resources/functionalities of the system, depending on the way the PDP has been configured. The task of testing the correctness of the implementation of the security policy is tedious and costly. In this paper, we propose a new approach to reuse and automatically adapt existing functional test cases for specifically testing the security mechanisms. It includes a two step dynamic analysis technique based on mutation applied to security policies (RBAC, XACML, OrBAC). The method is applied to Java programs and provides tools for performing the two steps of the dynamic analyses. Three empirical case studies provide fruitful results and a first proof of concepts for this approach, e.g. by comparing its efficiency to an error-prone manual adaptation task.