What is the test for determining whether a seizure occurred within the meaning of the Fourth Amendment?

"Whether a seizure occurred within the meaning of the Fourth Amendment is a mixed question of law and fact qualifying for independent review. [Citations.] Accordingly, 'we review the trial court's findings of historical fact under the deferential substantial evidence standard, but decide the ultimate constitutional question independently. [Citations.]' [Citation.] We must accept factual inferences in favor of the trial court's ruling. [Citation.] If there is conflicting testimony, we must accept the trial court's resolution of disputed facts and inferences, its evaluations of credibility, and the version of events most favorable to the People, to the extent the record supports them. [Citations.]" (People v. Zamudio (2008) 43 Cal.4th 327, 342.)