As his publisher stands trial for copyright infringement, Da Vinci Code author Dan Brown testified yesterday that, although he did use the Random House nonfiction book The Holy Blood and the Holy Grail in his research, he didn't copy squat. But of course he would say that if Holy Blood's scribes prevail in court, the May 19 release of the Code feature film starring Tom Hanks could be delayed indefinitely. And who wants to disappoint Tom Hanks?