What is the test for establishing the credibility of the sole witness in a criminal case?

Hearns, 18 A.D.2d at 923, 238 N.Y.S.2d 173 ; McFarland v. Smith, 611 F.2d 414, 419 [2d Cir.1979] [The credibility of the state's witness( ) should depend on an assessment of many pertinent factors, but the state should not be entitled to have its witness's credibility enhanced simply because (the witness is) not (a) member( ) of a group that might be prejudiced against the defendant] ). All the more so where the case turns on the credibility of the sole witness (People v. Robinson, 17 N.Y.3d 868, 870, 933 N.Y.S.2d 192, 957 N.E.2d 761 [2011] ).