Abstract: A test rig for testing a blade bearing of a wind turbine blade is provided. The blade bearing includes a first part and a second part that is rotatable about an axial direction with respect to the first part. The test rig includes a bearing support, which is configured to be mounted to the first part of the blade bearing, a shaft element, which is configured to be mounted to the second part of the blade bearing and able to rotate with respect to the bearing support. A test load unit is configured to apply a load in the axial direction to the shaft element. The test load unit includes at least one actuator that is controllable to apply the load.