What is the test for establishing that a party to a contract is entitled to a right to continue to work as a teacher?

We have previously noted that "liberty" or "property" protected by due process need not always flow from guaranty under state law or the Constitution. Huntley v. Community School Board of Brooklyn, 543 F.2d 979, 986 n. 8 (2d Cir.1976), cert. denied, 430 U.S. 929, 97 S.Ct. 1547, 51 L.Ed.2d 773 (1977), appeal after remand, 579 F.2d 738 (2d Cir.1978). Where the independent source of a property interest is a private contract, the state cannot transgress on the claim of entitlement to continued employment without due process of law. ³