The test is one of the approaches commonly used for validating systems to ensure qualitative and quantitative implementation requirements. In this paper, we interest in formal testing using graph transformation, thus we propose an approach for translating a Durational Actions Timed Automata model (DATA*) with a high number of states into a timed refusals region graph (TRRG) for creating a canonical tester and generating test cases using graph transformation. Though, our approach allows to generate automatically a visual modeling tool for DATA*, TRRG and the canonical tester. The cost of building a visual modeling tool from scratch is prohibitive. Meta- modeling approach is useful to deal with this problem since it allows the modeling of the formalisms themselves, by means of graph grammars. The meta-modeling tool AToM3 is used.