What is the test for a jury to convict a defendant on the testimony of an accomplice at the guilt phase of a trial?

accomplice alone." (People v. Howard (2008) 42 Cal.4th 1000, 1021-1022, italics omitted; see 1111 [accomplice testimony must be corroborated by "other evidence as shall tend to connect the defendant with the commission of the offense"].)

Error in failing to instruct the jury on consideration of accomplice testimony at the guilt phase of a trial constitutes state-law error, and a reviewing court must evaluate whether it is reasonably probable that such error affected the verdict. (People v. Wisenhurst (2008) 44 Cal.4th 174, 214.)

Any error in failing to instruct the jury that it could not convict defendant on the testimony of an accomplice alone is harmless if there is evidence corroborating the accomplice's testimony." 'Corroborating evidence may be slight, may be entirely circumstantial, and need not be sufficient to establish every element of the charged offense.' " (People v. Williams (2008) 43 Cal.4th 584, 636.)