What is the test for equal protection and due process in criminal trials?

for procedures in criminal trials which allow no invidious discriminations between persons and different groups of persons. Both equal protection and due process emphasize the central aim of our entire judicial systemall people charged with crime must, so far as the law is concerned, stand on an equality before the bar of justice in every American court. " ( Griffin v. Illinois (1956) 351 U.S. 12, 17, 76 S.Ct. 585, 100 L.Ed. 891 ( Griffin ).)