I don't know what that contract states but I am sure they are referring to stepping through there ceiling, drop your ladder through there window, etc. I can't see how you can be responsible for testing something and it fails. If that,s the case we could not check anything.
If you tested a GFCI breaker and it would not reset and the owner said it always worked and you should pay for it, Would you? no it failed. That's all I am saying. Filling a drain pan I would think is testing and not destructive.
If I Filled yours and it leaked I will make sure I am out of town for awhile when you find out..........
