What is the test for abuse of discretion when a defendant seeks to obtain DNA testing on a vibrator that was removed from the rectum of a dead person?

Defendant next argues the trial court abused its discretion by denying his request to obtain DNA testing on the vibrator that was removed from the corpse's rectum. It is true an indigent defendant is entitled to reasonably necessary ancillary services. (People v. Guerra (2006) 37 Cal.4th 1067, 1085.) But ancillary services are required only to "the minimum assistance necessary to assure [an indigent defendant] 'a fair opportunity to present his defense' and 'to participate meaningfully in [the] judicial proceeding.' " (Medina v. California (1992) 505 U.S. 437, 444-445 [120 L.Ed.2d 353].) A trial court's order is presumed correct and will be reversed only for an abuse of discretion. (Corenevsky v. Superior Court (1984) 36 Cal.3d 307, 319-321.)