Today we can see a significant increase in testing tools available for both the developer and the tester. Those tools aim at the testing of system implementation and vary according to the implementation paradigm, the programming language or the type of errors they seek to detect. In this paper, we present TAPIR, a white-box testing framework for Object-Oriented Programming. It was designed and implemented to detect failures in the sequence of calls that objects make. In that sense, we rely on Message Sequence Specification and Aspect-Oriented Programming. Hence, TAPIR can be used in any Java project without the need to modify the implementation of such a project. Our framework is open source and is freely available.Workshop: WIS – Ingeniería de SoftwareRed de Universidades con Carreras en Informática