This paper proposes a comprehensive model for test planning in a core-based environment. The main contribution of this work is the use of several types of TAMs and the consideration of different optimization factors (area, pins and test time) during the global TAM and test schedule definition. This expansion of concerns makes possible an efficient yet fine-grained search in the huge design space of a reuse-based environment. Experimental results clearly show the variety of trade-offs that can be explored using the proposed model, and its effectiveness on optimizing the system test design.