Yes, I am referring to debugging, if that means all certification done prior to end-users trying anything.
I do not approve of the concept of user tests. When the system is delivered to the user, there should be no bugs.
Any bug found is a disgrace to the team as well as the programmer whose module was in error.
Remember the Kriegspiel Referee
where we individually debugged various design modules.
The first time I took the individually debugged modules from Pete, Mennonite and Michael Calkins and integrated them with mine, the program magically worked and required no user testing.
Well, there is an exception whereby users note that even though everything works perfect per written specifications, they are not satisfied anyway because they are, in a sense, debugging their own requirements.
We had a few cases like that in the Kriegspiel Referee where the actual playing of a chess game pointed out problems that were unforeseen.
So I would hope when user testing starts, it is clear that problems found are due to the user changing his mind and wanting something different than originally documented.