@@ -274,14 +274,15 @@ def test_find_adaptive_nonbmp(self):
         # uses ASCII, so the UCS4 variant of adaptive_find never ran.
         a, b = '\U0001d11e', '\U0001d11f'
         for N in 1000, 10_000:
-            A, B = a * N, b * N
-            haystack = A + A + B + A + A
-            needle = A + B + B + A
-            self.assertEqual(haystack.find(needle), -1)
-            self.assertEqual(haystack.count(needle), 0)
-            combined = haystack + needle
-            self.assertEqual(combined.find(needle), len(haystack))
-            self.assertEqual(combined.count(needle), 1)
+            with self.subTest(N=N):
+                A, B = a * N, b * N
+                haystack = A + A + B + A + A
+                needle = A + B + B + A
+                self.assertEqual(haystack.find(needle), -1)
+                self.assertEqual(haystack.count(needle), 0)
+                combined = haystack + needle
+                self.assertEqual(combined.find(needle), len(haystack))
+                self.assertEqual(combined.count(needle), 1)
 
     def test_find(self):
         string_tests.StringLikeTest.test_find(self)