What is the test for dismissing an information or a misdemeanor complaint in the interest of justice?

Criminal Procedure Law 170.40 provides for the dismissal of an information or a misdemeanor complaint or count thereof "in the interest of justice ... when, even though there may be no basis for dismissal as a matter of law ... such dismissal is required as a matter of judicial discretion by the existence of some compelling factor, consideration or circumstance clearly demonstrating that conviction or prosecution of the defendant upon such accusatory instrument or count would constitute or result in injustice." The power to dismiss on such ground is committed to the trial court's discretion and it should be "exercised sparingly and only in that rare and unusual case where it cries out for fundamental justice beyond the confines of conventional considerations" (People v. Harmon, 181 A.D.2d 34, 36 [1st Dept 1992] [citations and internal quotation marks omitted] ).