What is the test for overturning a federal court's denial of a habeas corpus petition?

A district court's denial of habeas corpus petition is reviewed de novo. Shah v. United States, 878 F.2d 1156, 1159 (9th Cir.1989). To the extent it is necessary to review findings of fact, the clearly erroneous standard applies. Norris v. Risley 878 F.2d 1178, 1180 (9th Cir.1989).

A guilty plea will not be set aside after sentencing unless a manifest injustice would result. U.S. v. Hoyos, 892 F.2d 1387 (9th Cir.1989). The voluntariness of a guilty plea, however, is subject to de novo review. U.S. v. Zweber, 913 F.2d 705, 710 (9th Cir.1990). The denial of an evidentiary hearing on a Section 2255 motion will not be disturbed on appeal absent abuse of discretion. Shah v. United States, 878 F.2d 1156, 1159 (9th Cir.1989).