bpo-46542: test_json uses support.infinite_recursion() (GH-30972)

Fix test_json tests checking for RecursionError: modify these tests
to use support.infinite_recursion().

Lib/test/test_json/test_recursion.py

@@ -1,3 +1,4 @@
+from test import support
 from test.test_json import PyTest, CTest
 
 
@@ -69,10 +70,13 @@ class TestRecursion:
         # test that loading highly-nested objects doesn't segfault when C
         # accelerations are used. See #12017
         with self.assertRaises(RecursionError):
+            with support.infinite_recursion():
                 self.loads('{"a":' * 100000 + '1' + '}' * 100000)
         with self.assertRaises(RecursionError):
+            with support.infinite_recursion():
                 self.loads('{"a":' * 100000 + '[1]' + '}' * 100000)
         with self.assertRaises(RecursionError):
+            with support.infinite_recursion():
                 self.loads('[' * 100000 + '1' + ']' * 100000)
 
     def test_highly_nested_objects_encoding(self):
@@ -81,8 +85,10 @@ class TestRecursion:
         for x in range(100000):
             l, d = [l], {'k':d}
         with self.assertRaises(RecursionError):
+            with support.infinite_recursion():
                 self.dumps(l)
         with self.assertRaises(RecursionError):
+            with support.infinite_recursion():
                 self.dumps(d)
 
     def test_endless_recursion(self):
@@ -93,6 +99,7 @@ class TestRecursion:
                 return [o]
 
         with self.assertRaises(RecursionError):
+            with support.infinite_recursion():
                 EndlessJSONEncoder(check_circular=False).encode(5j)
 
 

Misc/NEWS.d/next/Tests/2022-01-28-01-17-10.bpo-46542.xRLTdj.rst

@@ -0,0 +1,2 @@
+Fix ``test_json`` tests checking for :exc:`RecursionError`: modify these tests
+to use ``support.infinite_recursion()``. Patch by Victor Stinner.