Just reading about this very subject (sorry vid from the niceic ) and above absolutely correct of course, Do all your tests and record on the actual certificate that you will finally issue. Apparently they will accept a partially completed certificate as enough evidence the installation is safe to connect to, you can then do the live tests on the same certificate. Job done.
Actually, I rather like the idea of a death test. Could be a new way of testing RCDS, or if re wirables have the correct fuse wire in them. There could be a mini course in how to do them, actualy best if i shut up.