What is the test for obtaining consent for a search?

Finding the knife and methamphetamine "eight-balls" on defendant's person, Flores asked defendant if the nearby backpack belonged to him and, if so, whether he consented to its inspection. Defendant answered both questions in the affirmative. (See People v. James, supra, 19 Cal.3d at p. 113 ["[T]here is no talismanic phrase which must be uttered by a suspect in order to authorize a search."].) There was no evidence Flores or his partner "displayed their weapons or other signs of force," "made any improper inducements to obtain consent," or invoked " 'the right to search without permission.' " (People v. Hernandez (1988) 199 Cal.App.3d 1182, 1188.)