What is the test for an ex post facto violation in a civil case?

"Whether a statutory scheme is civil or criminal under the ex post facto doctrine is first of all a question of statutory construction. We consider the statute's text and structure to determine the legislative objective. If we conclude that the statute as applied retroactively was intended to punish, then our inquiry is over and we will find an ex post facto violation. [Citation.]" ( Roman Catholic Bishop of Oakland v. Superior Court , supra , 128 Cal.App.4th at p. 1169, 28 Cal.Rptr.3d 355.)