Fix test for RTNE

Author: awf

src/gfloat/round.py

@@ -106,6 +106,15 @@ def round_float(
             case RoundMode.TiesToEven:
                 should_round_away = delta > 0.5 or (delta == 0.5 and code_is_odd)
             case RoundMode.Stochastic:
+                ## RTNE delta to srbits
+                d = delta * 2.0**srnumbits
+                floord = np.floor(d).astype(np.int64)
+                d = floord + (
+                    (d - floord > 0.5) or ((d - floord == 0.5) and _isodd(floord))
+                )
+
+                should_round_away = d > srbits
+            case RoundMode.StochasticNearly:
                 should_round_away = delta > (0.5 + srbits) * 2.0**-srnumbits
             case RoundMode.StochasticFast:
                 should_round_away = delta > srbits * 2.0**-srnumbits

test/test_round.py

@@ -494,7 +494,7 @@ def test_round_roundtrip(round_float: Callable, fi: FormatInfo) -> None:
     "v, srnumbits, expected_up",
     (
         (259, 3, 0.0 / 8),
-        (259, 5, 1.0 / 32),
+        (259, 5, 2.0 / 32),
         (277, 3, 3.0 / 8),
         (288, 3, 0.5),
         (311, 3, 7.0 / 8),