What is the test for a hearsay exception to the hearsay rule?

Defendant has failed to present a similarly compelling case. To begin with, foundational prerequisites are fundamental to any exception to the hearsay rule. (Chambers v. Mississippi, supra, 410 U.S. at p. 302, 93 S.Ct. at p. 1049; California v. Green (1970) 399 U.S. 149, 154, 90 S.Ct. 1930, 1933, 26 L.Ed.2d 489; cf. Washington v. Texas (1967) 388 U.S. 14, 23, fn. 21, 87 S.Ct. 1920, 1925, fn. 21, 18 L.Ed.2d 1019 [state may provide for testimonial privileges and nonarbitrary rules disqualifying certain witnesses].) As a general proposition, criminal defendants are not entitled to any deference in the application of these constraints but, like the prosecution, "must comply with established rules of procedure and evidence designed to assure both fairness and reliability in the ascertainment of guilt and innocence." ( Chambers v. Mississippi, supra, 410 U.S. at p. 302, 93 S.Ct. at p. 1049.)