This paper presents our Design for Testability reuse approach implemented in the allocation for testability system IDAT. In the context of High-Level Synthesis for Testability, the allocation for testability process mainly consists in searching for the best cost/quality trade-off between the designer requirements and testability means which can be proposed by the system, considering the available components in the library and the possibility of generating additional testability structures. The cost/quality trade-off is also based on the result of the testability analysis process.