What is the test for a jury to convict an appellant of sexual assault?

We emphasize that our task is not to decide whether we believe the evidence at trial established appellant's guilt beyond a reasonable doubt, but to determine whether substantial evidence supports the conclusion of the trier of fact. We must view the evidence in the light most favorable to the judgment, presume in support of the judgment the existence of every fact the jury could reasonably deduce from that evidence, and determine whether the record discloses substantial evidence such that a reasonable trier of fact could find the appellant guilty [139 Cal.App.3d 240] beyond a reasonable doubt. (People v. Johnson (1980) 26 Cal.3d 557, 576-578, 162 Cal.Rptr. 431, 606 P.2d 738.)