Flood testing a waterproofing system before it is tiled is a good practice. If a leak is found at this stage, it is very easily repaired as opposed to after tiling when a leak is a major problem.
There are some key points to consider before and after flood testing.
1. Ensure your membrane is fully cured. Check with manufacturer
This particular product was ready for flood testing after just 12 hours
2. Respect the stand down period after the test has been carried out. Again check with manufacturer, generally 24 hours