What is the test for whether a defendant aided and abetted a crime?

"'Whether defendant aided and abetted the crime is a question of fact, and on appeal all conflicts in the evidence and reasonable inferences must be resolved in favor of the judgment.' (People v. Mitchell (1986) 183 Cal.App.3d 325, 329.)" (People v. Campbell (1994) 25 Cal.App.4th 402, 409.)

"'All persons concerned in the commission of a crime, . . . whether they directly commit the act constituting the offense, or aid and abet in its commission, . . . are principals in any crime so committed.' (Pen. Code, 31, [citations].) Thus, a person who aids and abets a crime is guilty of that crime even if someone else committed some or all of the criminal acts. [Citation.]" (People v. McCoy (2001) 25 Cal.4th 1111, 1116-1117.) "Factors to be considered by the trier of fact in determining 'whether one is an aider and abettor include presence at the scene of the crime, failure to take steps to

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