3D IC testing is one of the major concern in the semiconductor industry today. Multiple subsequent testing of partial stack during 3D assembly is required due to the die stacking steps of thinning, alignment and bonding. In this paper we address the problem of minimizing the total time of partial stack and complete stack testing. We analyze how the stacking sequence of different System-on-Chips (SOCs) in a 3D Stacked Integrated Circuit (SIC) affects the total test time. We propose an algorithm to find this stacking sequence to achieve the minimum test time. Our algorithm is run on ITC'02 benchmarks and the results are shown.