Recently the usModuleTest fails on our Ubuntu CI clients as the Load() methods of the TestDriver's activator isn't called anymore. It probably started to fail with an upgrade of the minimum required version of CMake and changed policies/properties of targets. The symbol _us_module_activator_instance_main is not exported anymore but it has to be for dlsym() to be able to return its address at runtime. CMake now has an ENABLE_EXPORTS target property which seems to be necessary for executables to actually export their symbols as requested with the according export macros.