What is the test for enforceability of a written contract where the contract states that the parties intended to enforce the terms?

"`"It is axiomatic that a contract is to be interpreted so as to give effect to the intention of the parties as expressed in the unequivocal language employed"' [citations]. Thus, `clear, complete writings should generally be enforced according to their terms' [citation]. . . . The rule has even greater force in the context of real property transactions, `where commercial certainty is a paramount concern' [citation], and where, as here, the instrument was negotiated between sophisticated, counseled business people negotiating at arm's length [citation]." (Wallace v. 600 Partners Co. (1995) 86 N.Y.2d 543 [658 N.E.2d 715, 717, 634 N.Y.S.2d 669].)