What is the test for ineffective assistance of counsel?

" ' " 'In order to demonstrate ineffective assistance of counsel, a defendant must first show counsel's performance was "deficient" because his "representation fell below an objective standard of reasonableness . . . under prevailing professional norms." [Citations.] Second, he must also show prejudice flowing from counsel's performance or lack thereof. [Citation.] Prejudice is shown when there is a "reasonable probability that, but for counsel's unprofessional errors, the result of the proceeding would have been different. A reasonable probability is a probability sufficient to undermine confidence in the outcome." ' " ' [Citation.]" (People v. Vines (2011) 51 Cal.4th 830, 875-876, quoting People v. Lucas (1995) 12 Cal.4th 415, 436.)

We have already concluded that appellant's challenges to his sentence based on the prohibition against "unusual" punishment and the court's reasons for imposing the middle term are unavailing. The only question remaining, therefore, is whether defense counsel's representation was constitutionally deficient based on his failure to ask the court to strike the great bodily injury enhancement. "Although section 1385 provides that a dismissal 'in furtherance of justice' may be ordered either on the motion of the district attorney, or on the court's motion, a defendant may invite the court to exercise its power by an application to strike a count or allegation of an accusatory pleading, and the court must consider evidence offered by the defendant in support of his assertion that the dismissal would be in furtherance of justice." (Rockwell v. Superior Court (1976) 18 Cal.3d 420, 441-442.)