This is why you use an inflatable test plug for the Kerdi Line Drain. Proline from Quick Drain USA. You can add in the flanged drain from ACO as well with this group.
There is no need for 10' of water in a flood test for a shower floor. Still a need for the inflatable test plug to test the no hub fitting.
Nukeman what plumbing code are you sourcing your information from? Did you look up that information on the John Bridge forum?
This reference is exactly why a little information is a dangerous thing. And sadly your wrong on this point. More sad is Roberto from Montreal agrees with you and he waterproofs showers in Canada for a living like me…. Scary.