Yes, there is an EN standard that regulates how crampons should behave to get the EN certification. Unfortunately the guide is not available for free, as far as I know.
The UIAA reccomendations mostly rely on top of the EU ones.
The only added requirement by UIAA is:
In the information to be supplied the manufacturer shall draw attention to the dangers of snow balling up under the crampons when used in snow and shall advise the user how to reduce the risk.
So, I don't know what are those tests, but yes there is at least one standard (or two, if you may dare to count the UIAA as another one).
I would contact the ebay seller asking informations about this. There's no mention to any certification in the listing though so those crampons are likely not certified by any mean.