What is the test for dismissing a petition for writ of habeas corpus?

We review de novo the dismissal of a petition for writ of habeas corpus. Sanders v. Ratelle, 21 F.3d 1446, 1451 (9th Cir. 1994). When the district court denies habeas relief without an evidentiary hearing, it must make specific findings and conclusions on the petitioner's assertions to show that it has independently reviewed the record. Lincoln v. Sunn, 807 F.2d 805, 808-09 (9th Cir. 1987).