Test scheduling for core-based SoCs is a challenging problem. Test schedules must be crafted with the objectives of minimizing testing time and ATE vector memory requirements, to reduce test cost, under the constraints of total available test access mechanism (TAM) width. Prior research in test scheduling has mainly used search procedures like ILP and rectangle packing to solve this problem, but these approaches are inherently computationally expensive. In this paper we describe a novel algorithm to solve the test scheduling problem using a combination of network flow algorithms, malleable job scheduling and reconfigurable wrapper design. Our approximation algorithm has polynomial time complexity and produces schedules close to the theoretical lower bound. Extensive experimental results using the new ITC?02 SoC benchmarks validate the quality of our solutions.