A ponding test is done by sealing up all drainage exits in the area and flooding the entire area with 1-3 inches of water. The test may be carried out for a period of 24-72 hours depending on the situation.
Observations on the water level should be steady without any wetness on the outside wall and bottom floor (one floor below if more than one storey)

Should be both basin & wc area as long within the bathroom floor being wet area thus would be exposed to standing/ponding water by the user.
Installed bathroom tiles and grouting compound must be waterproof.

You can also add in a layer of waterproofing membrane if required to the manufacturer's installation guidelines

Yes..

Already passed the ponding test.. A second test might fail due to outside reasons beyond the responsibility of the development..
Maybe a new extension that damaged the water proofing ..
That is the reason