What is the test for ineffective assistance of counsel?

"To prevail on a claim of ineffective assistance of counsel, a defendant must show both that counsel's performance was deficient and that the deficient performance prejudiced the defense. [Citations.] Counsel's performance was deficient if the representation fell below an objective standard of reasonableness under prevailing professional norms. [Citation.] Prejudice exists where there is a reasonable probability that, but for counsel's errors, the result of the proceeding would have been different. [Citation.]" (People v. Benavides (2005) 35 Cal.4th 69, 92-93.) However, " '[if] the record on appeal sheds no light on why counsel acted or failed to act in the manner challenged[,] . . . unless counsel was asked for an explanation and failed to provide one, or unless there simply could be no satisfactory explanation,' the claim on appeal must be rejected." (People v. Wilson (1992) 3 Cal.4th 926, 936.)