gh-122163: Add notes for JSON serialization errors (GH-122165)

This allows to identify the source of the error.

1 files changed, 10 insertions, 8 deletions

diff --git a/Lib/test/test_json/test_recursion.py b/Lib/test/test_json/test_recursion.py
index 164ff2013eb..290207e9c15 100644
--- a/Lib/test/test_json/test_recursion.py
+++ b/Lib/test/test_json/test_recursion.py
@@ -12,8 +12,8 @@ class TestRecursion:
         x.append(x)
         try:
             self.dumps(x)
-        except ValueError:
-            pass
+        except ValueError as exc:
+            self.assertEqual(exc.__notes__, ["when serializing list item 0"])
         else:
             self.fail("didn't raise ValueError on list recursion")
         x = []
@@ -21,8 +21,8 @@ class TestRecursion:
         x.append(y)
         try:
             self.dumps(x)
-        except ValueError:
-            pass
+        except ValueError as exc:
+            self.assertEqual(exc.__notes__, ["when serializing list item 0"]*2)
         else:
             self.fail("didn't raise ValueError on alternating list recursion")
         y = []
@@ -35,8 +35,8 @@ class TestRecursion:
         x["test"] = x
         try:
             self.dumps(x)
-        except ValueError:
-            pass
+        except ValueError as exc:
+            self.assertEqual(exc.__notes__, ["when serializing dict item 'test'"])
         else:
             self.fail("didn't raise ValueError on dict recursion")
         x = {}
@@ -60,8 +60,10 @@ class TestRecursion:
         enc.recurse = True
         try:
             enc.encode(JSONTestObject)
-        except ValueError:
-            pass
+        except ValueError as exc:
+            self.assertEqual(exc.__notes__,
+                             ["when serializing list item 0",
+                              "when serializing type object"])
         else:
             self.fail("didn't raise ValueError on default recursion")