Hi,
There are quite a few ‘Teller practice notes’ in the catalogue, but the assignment to the issuer doesn't seem to be aligned:
https://en.numista.com/catalogue/index.php?r=Teller+practice
For most it's China but either with or without ruling authority, though some like AUD and EUR have been assigned to Australia and the Eurozone (though 1 denomination is with China), respectively. I have no strong views on where they should go, but the current situation is quite inconsistent.