In reply to chr_sue:
In reply to UVM_LOVE:
uvm_callback is an extension of uvm_object. But you are trying to use it as a component when extenting the callback to a test. The test has to be a component.
But don’t know why it does not make an error.
There is no any Compile/Elaborate/Simulation Error messages and looks working good.
As you can see the reference code/site what I have linked even it was used in there as per object into component test class.