What is the test for a writ of habeasas corpus?

A writ of habeas corpus "is unavailable for alleged error in the interpretation or application of state law." Middleton v. Cupp, 768 F.2d 1083, 1085 (9th Cir.1985) (citation omitted), cert. denied, 478 U.S. 1021 (1986). Although it is not a customary practice, in California a trial judge has the discretion to reserve a ruling on the admissibility of a defendant's prior convictions until the defendant has testified. See People v. Washington, 259 Cal.Rptr. 307, 311 (Cal.Ct.App.1989). "[T]o raise and preserve for review the claim of improper impeachment with a prior conviction, a defendant must testify." Luce v. United States, 469 U.S. 38, 43 (1984).