What is the test for appointing counsel in a habeas petition?

The Criminal Justice Act additionally provides that whenever the court "determines that the interests of justice so require, representation may be provided for any financially eligible person who ... is seeking relief under ... 2255 of title 28." 18 U.S.C. 3006A(a)(2)(B). The decision to appoint counsel in a habeas petition is within the discretion of the district court. See Chaney v. Lewis, 801 F.2d 1191, 1196 (9th Cir. 1986), cert. denied, 481 U.S. 1023 (1987). Appointment of counsel in a habeas petition is mandatory only when the circumstances of a particular case indicate that appointed counsel is necessary to prevent due process violations. See Id.