What is the test for ineffective assistance of counsel?

Where, as here, the claim is based on an alleged omission by counsel and the record on appeal does not contain an explanation for the omission, we must reject the claim unless there could be " ' "no satisfactory explanation" ' " for counsel's conduct. (People v. Mendoza Tello (1997) 15 Cal.4th 264, 266-267 [reversing a holding of ineffective assistance of counsel where record did not show why counsel failed to move to suppress evidence obtained during a warrantless search because counsel was "perhaps" aware that the officer had a justification for the search].) In other words, if there could be a reasonable explanation for counsel's decision, the claim of ineffective assistance of counsel must fail.