docstr: Test PyUnicode_AppendAndDel()
docstr_tok: ["Test","PyUnicode_AppendAndDel","(",")"]
code: def test_appendanddel(self):
      """Test PyUnicode_AppendAndDel()"""
      from _testcapi import unicode_appendanddel as appendanddel
  
      strings = [
          "abc",
          "\xa1\xa2\xa3",
          "\u4f60\u597d\u4e16",
          "\U0001f600\U0001f601\U0001f602",
      ]
      for left in strings:
          left = left[::-1]
          for right in strings:
              self.assertEqual(appendanddel(left, right), left + right)
  
      self.assertRaises(SystemError, appendanddel, "abc", b"abc")
      self.assertRaises(SystemError, appendanddel, b"abc", "abc")
      self.assertRaises(SystemError, appendanddel, b"abc", b"abc")
      self.assertRaises(SystemError, appendanddel, "abc", [])
      self.assertRaises(SystemError, appendanddel, [], "abc")
      self.assertRaises(SystemError, appendanddel, [], [])
      self.assertRaises(SystemError, appendanddel, NULL, "abc")
      self.assertRaises(SystemError, appendanddel, "abc", NULL)
  
imports: import unittest
  import sys
  from test import support
  from test.support import import_helper
label_desc: Use image node_id 6 for calling the CAPITest obj's underlying member method code with example usage: obj.test_appendanddel() without return types