What is the test for determining whether a trial attorney is competent to stand trial?

appeal, competency is presumed unless the record affirmatively excludes a rational basis for the trial attorney's choice. [Citations.]" (People v. Musselwhite (1998) 17 Cal.4th 1216, 1260, original italics.)

In the present case, "the appellate record sheds no light on why trial counsel acted as he did; he was not asked to explain his performance; although we may doubt that a satisfactory explanation could be provided, we are unable to conclude that it could not. Thus, we must reject defendant's point." (People v. Bell (1989) 49 Cal.3d 502, 546, fn. omitted.)