What is the legal test for a lawyer who makes a tactical error in making a motion?

There is a strong presumption that counsel's conduct falls within the wide range of reasonable professional assistance. Tactical errors are generally not deemed reversible. Counsel's decisionmaking is evaluated in the context of the available facts. To the extent the record fails to disclose why counsel acted or failed to act in the manner challenged, appellate courts will affirm the judgment unless counsel was asked for an explanation and failed to provide one, or there could be no satisfactory explanation. Prejudice must be affirmatively proved. The record must affirmatively demonstrate a reasonable probability that, but for counsel's unprofessional errors, the result of the proceeding would have been different. (People v. Maury (2003) 30 Cal.4th 342, 389.) Attorneys are not expected to engage in tactics or to file motions that are futile. (People v. Price (1991) 1 Cal.4th 324, 386-387.)