What is the test for a plaintiff to recover damages under Section 1983 of the Civil Rights Act?

In order to recover damages for an allegedly unlawful conviction, a 1983 plaintiff must prove that the conviction or sentence has been reversed on direct appeal, expunged by executive order, declared invalid by a state tribunal authorized to make such determination, or called into question by federal court's issuance of a writ of habeas corpus. See Heck v. Humphrey, 114 S.Ct. 2364, 2372 (1994). If a judgment in favor of plaintiff on his civil rights damages claims will necessarily imply the invalidity of his conviction or sentence, the complaint must be dismissed unless the plaintiff can demonstrate that the conviction or sentence has already been invalidated. Id.