What is the test for a criminal offence under section 654 of the California Code of Criminal Procedure?

Under section 654, subdivision (a), "[a]n act or omission that is punishable in different ways by different provisions of law shall be punished under the provision that provides for the longest potential term of imprisonment, but" not "punished under more than one provision." By judicial gloss, the single punishment rule applies, not just for a single act, but for a single course of conduct. (Neal v. State of California (1960) 55 Cal.2d 11, 19 (Neal).) "Whether a course of criminal conduct is divisible and therefore gives rise to more than one act within the meaning of section 654 depends on the intent and objective of the actor. If all of the offenses were incident to one objective, the defendant may be punished for any one of such offenses but not for more than one." (Ibid.)