What is the test for the doctrine of "just compensation" in the context of eminent domain?

Implicit in appellants' due process argument is the theory that the government exercises its power of eminent domain when it incorrectly overassesses a taxpayer and hence the government must pay just compensation in the form of interest for the taking of the property. There is no basis in law for such a theory. "Under our constitution, private property may be taken for public use, either by the exercise of the right of eminent domain or by taxation. These are sovereign powers which are separate and distinct from each other, and the power which is conferred upon municipalities under the proceedings authorized by the act in question, as far as assessing the lands for special benefits are concerned, are referable solely to the exercise by the state of its sovereign power of taxation conferred upon municipalities as its governmental agents." (Clute v. Turner (1909) 157 Cal. 73, 79, 106 P. 240.)