What is the legal test for consent under the Fourth Amendment?

" 'The standard for measuring the scope of a suspect's consent under the Fourth Amendment is that of "objective" reasonableness--what would the typical reasonable person have understood by the exchange between the officer and the suspect? [Citations.]' [Citation.] Generally, the scope of a warrantless search is defined by its expressed object. [Citation.] A consensual search may not legally exceed the scope of the consent supporting it. [Citation.] Whether the search remained within the boundaries of the consent is a question of fact to be determined from the totality of circumstances." (People v. Crenshaw (1992) 9 Cal.App.4th 1403, 1408, 1414-1415 [upholding removal of vent from car door as within scope of consent to a drug search].)

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