What is the test for "ex post facto" criminal legislation?

"[F]or a criminal or penal law to be ex post facto ... it must apply to events occurring before its enactment, and it must disadvantage the offender affected by it." (Weaver v. Graham (1981) 450 U.S. 24, 28-29, 101 S.Ct. 960, 964, 67 L.Ed.2d 17, fn. omitted.) Such laws include those which "(1) impose criminal liability for conduct innocent when it occurred, (2) increase the punishment prescribed for a crime at the time it was committed, or (3) by necessary operation and ' "in [their] relation to the offense, or [their] consequences, alter the situation of the accused to his disadvantage...." ' [Citations.]" (Conservatorship of Hofferber (1980) 28 Cal.3d 161, 180, 167 Cal.Rptr. 854, 616 P.2d 836.)