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

^3. "Although it arises in the context of a criminal trial, a competency hearing is a special proceeding, governed generally by the rules applicable to civil proceedings. [Citations.] A defendant is presumed competent unless the contrary is proven by a preponderance of the evidence." (People v. Lawley (2002) 27 Cal.4th 102, 131.)