There are cases where it can be useful to allow custom actions to do things like test configuration values. See CAS configuration in System Settings as an example.
In Instance Settings, CAS is a custom view and has a "Test Configuration" menu item.
In System Settings, there is no way to provide that same sort of "Test" functionality. The solution would be to allow contributing items to the "three-dots" menu of any given configuration. These items would generally be custom render commands that test or utilize the values of the currently saved configuration.