What is the test for a general denial of a claim of failure of consideration?

Defendants contend they established a triable issue of material fact of failure of consideration. Had they done so no objection could be raised on grounds of defects in the allegations of affirmative defense or the parol evidence rule. (Com.Code, 3306; see Richardson v. Lamp (1930) 209 Cal. 668, 670, 290 P. 14.) Where, as here, the plaintiff is not a holder in due course, a general denial puts in issue the question whether consideration was given for the note which recites that it was given for valuable consideration. (Pomeroy, supra, 552, p. 904.) Such a defense, because it challenges a facial claim of the note, is not subject to the parol evidence rule. That brings us to a predicate question, whether the defendants have shown a failure of consideration. We conclude that they have not. Rather the defense is in the nature of frustration of purpose, which defendants have not made out. ¹⁵