What is the test for corroborating the testimony of an alleged accomplice in a sexual assault case?

California law provides that accomplice testimony alone is insufficient for conviction. Cal. Penal Code 1111. CALCRIM 334 requires that accomplice testimony be corroborated. According to this instruction, before the testimony of an asserted accomplice can be considered as evidence against the accused, the jury must decide whether the witness was an accomplice to the crime. An accomplice is defined "as one who is liable to prosecution for the identical offense charged against the defendant on trial in the cause in which the testimony of the accomplice is given." Cal. Penal Code 1111. Being "subject to prosecution" requires that the witness either personally committed the crime, or knew of the criminal purpose of the person who did commit the crime, and intended to and did, in fact, aid, facilitate, promote, encourage or instigate the commission of the crime, or participate in a criminal conspiracy to commit the crime. See People v. Carrington, 47 Cal. 4th 145, 190-191, 97 Cal. Rptr. 3d 117 (2009).