What is the test for a defendant to be competent to stand trial?

"A criminal defendant must be competent to stand trial. 'A defendant is mentally incompetent [to stand trial] if, as a result of mental disorder or developmental disability, the defendant is unable to understand the nature of the criminal proceedings or to assist counsel in the conduct of a defense in a rational manner.' ( 1367, subd. (a).) If the trial court entertains any doubt as to the mental competence of a defendant, and the defendant's attorney concurs in that doubt, the court must recess proceedings and order that a hearing be held to determine whether the defendant, is competent to proceed. ( 1368, subds. (a), (b).)" (People v. Jernigan (2003) 110 Cal.App.4th 131, 135.)