What is the test for determining whether a procedural ruling in a habeas case was wrong?

jurists of reason would find it debatable whether the district court was correct in any procedural ruling. Slack v. McDaniel, 529 U.S. 473, 483-84 (2000).

In determining this issue, a court conducts an overview of the claims in the habeas petition, generally assesses their merits, and determines whether the resolution was debatable among jurists of reason or wrong. Id. It is necessary for an applicant to show more than an absence of frivolity or the existence of mere good faith; however, it is not necessary for an applicant to show that the appeal will succeed. Miller-El v. Cockrell, 537 U.S. at 338.