What is the test for a motion to suppress under the Fourth Amendment?

"Where, as here, a motion to suppress is submitted to the superior court on the preliminary hearing transcript, 'the appellate court disregards the findings of the superior court and reviews the determination of the magistrate who ruled on the motion to suppress, drawing all presumptions in favor of the factual determinations of the magistrate, upholding the magistrate's express or implied findings if they are supported by substantial evidence, and measuring the facts as found by the trier against the constitutional standard of reasonableness.' [Citation.] 'We exercise our independent judgment in determining whether, on the facts presented, the search or seizure was reasonable under the Fourth Amendment. [Citation.]' [Citation.] We affirm the trial court's ruling if correct under any legal theory." (People v. Hua (2008) 158 Cal.App.4th 1027, 1033.)

b. The Fourth Amendment's protection against unreasonable searches