What is the test for ineffective assistance of counsel?

A conviction must be reversed on the ground of ineffective assistance of counsel when it is shown that counsel's performance was not reasonably competent and there was a reasonable probability the result would have been more favorable in the absence of counsel's shortcomings. (People v. Cunningham (2001) 25 Cal.4th 926, 1003.) Here, appellant failed to show from the four corners of the record who the exculpatory witnesses were, what they would have testified, and why trial counsel did not call them. (See ibid. [claim of ineffective assistance must be rejected if it cannot be established based on the four corners of the record].) Appellant demonstrates neither the performance nor the prejudice aspect of his ineffective assistance claim.