A first workpiece includes first active pads, a first test pad, and a second test pad on a primary surface of the first workpiece, the first test pad electrically connected to the second test pad. A second workpiece includes second active pads, a third test pad, and a fourth test pad on a primary surface of the second workpiece. The first and second workpieces are bonded along an interface between the primary surface of the first workpiece and the primary surface of the second workpiece to bond the first active pads with the second active pads, bond the first test pad with the third test pad, and bond the second test pad with the fourth test pad. Connectivity detection circuits test electrical connectivity between the third test pad and the fourth test pad.