Add a failing test

Author: AlexWaygood

Lib/test/test_ast.py

@@ -1058,6 +1058,10 @@ def test_assignment_expression_feature_version(self):
         with self.assertRaises(SyntaxError):
             ast.parse('(x := 0)', feature_version=(3, 7))
 
+    def test_conditional_context_managers_parse_with_low_feature_version(self):
+        # regression test for gh-115881
+        ast.parse('with (x() if y else z()): ...', feature_version=(3, 8))
+
     def test_exception_groups_feature_version(self):
         code = dedent('''
         try: ...