test: ledger comparator compares labels exactly and numbers with NaN-equality

same_summary applied np.array_equal(equal_nan=True) to string metadata
('last_base_step'), a TypeError on the first D/B vs B/B ledger compare.
Numbers (bool/int/float/complex) still compare exactly with equal shapes
and NaN-equality; other values (window labels) compare by dtype and value.
New host test: a summary with string metadata equals itself, and changing
the window label, an integer, a nested float, a scalar or a NaN-bearing
array is detected in both directions. No assertion removed, no tolerance.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/validation/multigrid/test_refinement_blocked_base.py

@@ -362,10 +362,24 @@ def same_summary(a, b):
         return a.keys() == b.keys() and all(same_summary(a[k], b[k]) for k in a)
     if isinstance(a, (list, tuple)):
         return len(a) == len(b) and all(same_summary(x, y) for x, y in zip(a, b))
-    return np.array_equal(np.asarray(a), np.asarray(b), equal_nan=True)
+    a, b = np.asarray(a), np.asarray(b)
+    if a.dtype.kind in "biufc" and b.dtype.kind in "biufc":
+        return a.shape == b.shape and np.array_equal(a, b, equal_nan=True)
+    return a.dtype == b.dtype and np.array_equal(a, b)  # labels such as the window name
 
 
 class DenseBlockedRouteCPU(unittest.TestCase):
+    def test_same_summary_compares_labels_and_every_number(self):
+        ledger = {"window": "last_base_step", "time_start": 3, "total": {"force": [1.0, -2.0],
+                  "torque": 0.5}, "aperture": {"force": np.array([np.nan, 1.0])}}
+        self.assertTrue(same_summary(ledger, replace_value(ledger, ())))
+        for path, value in ((("window",), "last_substep"), (("time_start",), 4),
+                            (("total", "force"), [1.0, -2.000001]), (("total", "torque"), 0.25),
+                            (("aperture", "force"), np.array([0.0, 1.0]))):
+            with self.subTest(path=path):
+                self.assertFalse(same_summary(ledger, replace_value(ledger, path, value)))
+                self.assertFalse(same_summary(replace_value(ledger, path, value), ledger))
+
     def test_route_capability_matrix(self):
         context = Mock(activate=Mock(side_effect=AssertionError("CUDA reached")))
         periodic = config("periodic")
@@ -389,6 +403,14 @@ class DenseBlockedRouteCPU(unittest.TestCase):
         context.activate.assert_not_called()
 
 
+def replace_value(tree, path, value=None):
+    """Deep copy of a nested dict with the item at ``path`` replaced (no change for ())."""
+    if isinstance(tree, dict):
+        return {k: (value if path == (k,) else replace_value(v, path[1:], value) if path[:1] == (k,)
+                    else replace_value(v, (), None)) for k, v in tree.items()}
+    return np.array(tree, copy=True) if isinstance(tree, np.ndarray) else tree
+
+
 class DenseBlockedRouteParity(unittest.TestCase):
     """D/D vs D/B vs B/B, unshifted SRT, one circle or one velocity Jet; see module docstring."""