When reviewing a ruling on an unsuccessful motion to exclude evidence, what is the test for determining whether a search violated the Fourth Amendment?

" ' "When reviewing a ruling on an unsuccessful motion to exclude evidence, we defer to the trial court's factual findings, upholding them if they are supported by substantial evidence, but we then independently review the court's determination that the search did not violate the Fourth Amendment." ' [Citation.] This means that we must measure the facts, as found by the trial court, against the constitutional standard of reasonableness for the search and/or seizure [citation] but we 'decide for ourselves what legal principles are relevant, independently apply them to the historical facts, and determine as a matter of law whether there has been an unreasonable search and/or seizure.' [Citation.]" (People v. Hochstraser (2009) 178 Cal.App.4th 883, 894.)