Increasing the load capacity of spline-joints in shaft-gear connections, such as UHBR-aero-engines, leads to a lean and efficient design of the power train components, which can raise the resource efficiency of the supra-systems. An approach to increase the load capacity of spline-joints is to apply optimized surface treatments, such as coatings and laser structuring, which can reduce the risk of upcoming wear and fatigue phenomena. Pin-on-Disc tests show promising results for the wear behaviour of TiN + MoS2:Ti and TiN + DLC + MoS:Ti:C multi-layered coatings in terms of physical vapour deposition (PVD) in combination with laser structured surface topologies. To assess the potential of these surface treatments for spline-joints, tests under real working conditions with full-scale spline-joints need to be carried out. As the application is an UHBR-aero-engine gas turbine, component tests with spline-joints are not applicable in the application for economic reasons. Hence, a design for a test spline connection, as well as a test rig are required to investigate the wear and fatigue behaviour of surface treated spline-joints. The submitted paper addresses this subject by presenting the design approach of the test spline geometry based on a spline-joint simulation model and the design of the test rig that has been build up. This combination enables the generation of the required spline-joint gear-mesh characteristics for conclusive component tests. The necessary contact pressure and movement kinematic of the contact zones from the original application are realized throughout the test spline geometry in combination with the dedicated spline loads, respective the test-torque, rotational speed and prevailing spline misalignment, provided by the test rig.