A test in CIVIL PROCEDURE designed to establish that a complaint has met the minimum amount in controversy required for a court to have jurisdiction to hear the case. Under this test, if it is apparent from the face of the pleadings, to a "legal certainty" that the plaintiff cannot recover or was never entitled to the amount in the complaint, then the case will be dismissed.
For example, the existence of federal diversity jurisdiction on the part of a federal district court—one aspect of which is the presence of an amount in controversy in excess of $75,000—is a threshold QUESTION OF LAW, or one which must be determined by the judge at the start of the action by applying the legal-certainty test.
Glannon, Joseph W. 2001. Civil Procedure: Examples and Explanations. Gaithersburg, Md.: Aspen Law & Business.
Kane, Mary Kay. 1996. Civil Procedure in a Nutshell. 4th ed. St. Paul, Minn.: West Group.