What is the test for retroactivity in the context of search and seizure cases?

The teaching of these retroactivity cases is that if law enforcement officers reasonably believed in good faith that evidence they had seized was admissible at trial, the "imperative of judicial integrity" is not offended by the introduction into evidence of that material even if decisions subsequent to the search or seizure have broadened the exclusionary rule to encompass evidence seized in that manner.

See also Linkletter v. Walker, 381 U.S. 618, 636-40, 85 S.Ct. 1731, 14 L.Ed.2d 601 (1965).