What is the test for determining whether an action is based on contract rather than tort?

Whether an action is based on contract or tort depends upon the nature of the right sued upon, not the form of the pleading or relief demanded. If based on breach of promise it is contractual; if based on breach of a noncontractual duty it is tortious. (Voth v. Wasco Public Util. Dist., 56 Cal.App.3d 353, 356, 128 Cal.Rptr. 608.) If unclear the action will be considered based on contract rather than tort. (Id., at p. 357, 128 Cal.Rptr. 608.)