What is the test for corroboration of testimony of an alleged accomplice in a criminal case?

"A conviction cannot be had upon the testimony of an accomplice unless it be corroborated by such other evidence as shall tend to connect the defendant with the commission of the offense; and the corroboration is not sufficient if it merely shows the commission of the offense or the circumstances thereof." (Evid. Code, 1111.) Testimony within the meaning of Evidence Code section 1111 includes "'all oral statements made by an accomplice or coconspirator under oath in a court proceeding and all out-of-court statements of accomplices and coconspirators used as substantive evidence of guilt which are made under suspect circumstances. The most obvious suspect circumstances occur when the accomplice has been arrested or is questioned by the police.' [Citation.]" (People v. Williams (1997) 16 Cal.4th 153, 245.) In contrast, this rule does not apply when out-of-court statements are given under circumstances which cannot be called suspect. (Ibid.)