What is the test for abuse of a district court's decision whether to order a presentence study?

We review for abuse of discretion a district court's decision whether to order a presentence study. Cf. United States v. Bos, 917 F.2d 1178, 1183 (9th Cir.1990) (reviewing for abuse of discretion a district court's refusal to continue sentencing to accommodate defendant's request for a psychiatric examination under 18 U.S.C. Sec. 4244(b)).

Under 18 U.S.C. Sec. 4205(c), which was repealed but still applies to offenses committed before November 1, 1987, the district court "may order a study" of a defendant when the court "desires more information" prior to sentencing. Although trial courts are accorded virtually unfettered discretion in imposing pre-Sentencing Guidelines sentences, appellate review is available if the district court refused to exercise its discretion, for example, by automatically imposing the maximum term. United States v. Barker, 771 F.2d 1362, 1364 (9th Cir.1985). Moreover, a district court abuses its discretion in violation of the due process clause if it imposes the maximum sentence without allowing the probation violator an opportunity to present mitigating evidence. United States v. Diaz-Burgos, 601 F.2d 983, 985-86 (9th Cir.1979) (per curiam).