What is the test for consent to use of a search dog in a vehicle search?

The defendant argued that his consent to search did not extend to use of the dog. The appellate court disagreed, for two reasons: First, a canine sniff search performed on the exterior of a vehicle is minimally intrusive; and second, the defendant did not object to use of the dog. (37 F.3d at p. 516.) " 'Failure to object to the continuation of a vehicle search after giving general consent to search "is properly considered as an indication that the search was within the scope of the initial consent." ' " (Ibid., quoting U.S. v. [43 Cal.App.4th 772] Cannon (9th Cir.1994) 29 F.3d 472, 477, quoting United States v. Sierra-Hernandez (9th Cir.1978) 581 F.2d 760, 764, cert. den., 439 U.S. 936, 99 S.Ct. 333, 58 L.Ed.2d 333.)