What is the test for ineffective assistance of counsel?

"'Generally, a conviction will not be reversed based on a claim of ineffective assistance of counsel unless the defendant establishes both of the following: (1) that counsel's representation fell below an objective standard of reasonableness; and (2) that there is a reasonable probability that, but for counsel's unprofessional errors, a determination more favorable to defendant would have resulted. [Citations.] If the defendant makes an insufficient showing on either one of these components, the ineffective assistance claim fails.'" (People v. Foster (2003) 111 Cal.App.4th 379, 383.) "Generally,... prejudice must be affirmatively proved. [Citations.] 'It is not enough for the defendant to show that the errors had some conceivable effect on the outcome of the proceeding.... The defendant must show that 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.' [Citations.]" (People v. Ledesma (1987) 43 Cal.3d 171, 217-218.)