What is the test for determining whether a person has been classified as a "person" by the federal government?

To measure the present case by these principles, we now turn to Matter of Abrams v. Bronstein, 33 N.Y.2d 488, 492, 354 N.Y.S.2d 926, 310 N.E.2d 528, an equal protection case arising out of a compensation dispute, where the following test was suggested: after ascertaining "the basis of the classification involved and the governmental objective purportedly advanced * * * classification must then be compared to the objective to determine whether the classification rests 'upon some ground of difference having a fair and substantial relation' to the object for which it is proposed (Reed v. Reed, 404 U.S. 71, 76, 92 S.Ct. 251, 254, 30 L.Ed.2d 225 * * *)."