Advances in semiconductor design and manufacturing technology enable the design of complete systems on one IC. To develop these system ICs in a timely manner, traditional IC design in which everything is designed from scratch, is replaced by a design style based on embedding large reusable modules, the so-called cores. Effectively, the design of a core-based IC is partitioned over the core provider(s) and the system-chip integrator. The development of tests should follow the same partitioning. We describe the differences between traditional and core-based test development, and present an overview of current industrial approaches. We list the future challenges regarding standardization, tool development, and academic and industrial research.