What is the test for a section 995 motion to preserve the issue of the Fourth Amendment after a guilty plea?

credibility or weight of the evidence for that of the magistrate. [Citation.] On review by appeal . . . , the appellate court in effect disregards the ruling of the superior court and directly reviews the determination of the magistrate holding the defendant to answer. [Citations.]"³ (People v. Laiwa (1983) 34 Cal.3d 711, 718.)

A section 995 motion "preserve[s] the Fourth Amendment issue on an appeal following a guilty plea only when it appears from the transcript of the preliminary hearing that essential evidence was illegally obtained." (People v. Lilienthal (1978) 22 Cal.3d 891, 897.) On appeal, "[w]e must draw all presumptions in favor of the magistrate's factual determinations, and we must uphold the magistrate's express or

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