What is the test for a motion for summary acquittal under section 1118 of the California Penal Code?

On appeal, defendants contend the trial court erred in denying their Penal Code section 1118 motion. "Section 1118 was designed to terminate a prosecution for an offense or offenses at the earliest possible time when the prosecution's own evidence is insufficient to support a conviction. [Citations.]" (People v. Norris (2002) 95 Cal.App.4th 475, 479.) "Section 1118 . . . establishes a procedure for summary acquittal when the prosecution presents insufficient evidence of a criminal charge during its case-in-chief. It provides in relevant part, 'In a case tried by the court without a jury . . . the court on motion of the defendant or on its own motion shall order the entry of a judgment of acquittal of one or more of the offenses charged in the accusatory pleading after the evidence of the prosecution has been closed if the court, upon weighing the evidence then before it, finds the defendant not guilty of such offense or offenses.'" (Id. at p. 478.)

LAMC section 12.21, subdivision A.1(a)