This paper presents the development of a modularized hypermedia testing tool, called iAdaptTest, based entirely on e-learning specifications and discusses how this architecture improves the reusability and the interoperability of the learning data. All the categories of data,-that is-topics, user profiles, testing data, adaptive rules, and testing results are coded in XML format complying with Topic Maps, IMS LIP and IMS QTI. The data are stored in distinct files and can be independently shared across different educational applications. The paper concludes with an evaluation study concerning the creation of formative and summative assessments for adult seminars. Through focused interviews, the participants of the study identified the ability to share information and the multi-criteria adaptation options as the most important features of the system. Further, in the second phase of the evaluation the files produced were shared with other educational applications and thus it was verified that the learning data could be imported and rendered correctly.