What is the test for a motion to suppress a confession made under section 1538.5 of the California Criminal Code?

[204 Cal.App.3d 1236] The first, which is used rather infrequently, is a pretrial motion to suppress made under the common law rather than under any statutory authority. "Courts of this state have long recognized the existence of a common law motion to suppress illegally obtained statements. [Citations.] However, this common law motion differs from a section 1538.5 motion in its effect in subsequent proceedings.... '[A]ny ruling on the admissibility of an admission or confession made at such a motion is not binding on the court if the People again offer the evidence at the trial.' [Citations.]" (People v. Superior Court (Zolnay), supra,

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