Concretization is one of the most labor-intensive phases of the model-based testing process. This study concentrates on concretization of the abstract tests generated from the test models. The purpose of the study is to design and implement a structure to automate this phase which can reduce the required effort specially in every system update. The structure is completed and discussed as an extension on a model-based testing tool named ModelJUnit using adaptation approach. In this structure, the focus is mainly on bridging the gap in data-level between the SUT and the model.