code: def test_wstring_at(self):
      p = create_unicode_buffer("Hello, World")
      a = create_unicode_buffer(1000000)
      result = memmove(a, p, len(p) * sizeof(c_wchar))
      self.assertEqual(a.value, "Hello, World")
  
      self.assertEqual(wstring_at(a), "Hello, World")
      self.assertEqual(wstring_at(a, 5), "Hello")
      self.assertEqual(wstring_at(a, 16), "Hello, World\0\0\0\0")
      self.assertEqual(wstring_at(a, 0), "")
  
file_path: cpython/Lib/test/test_ctypes/test_memfunctions.py
imports: import sys
  import unittest
  from test import support
  from ctypes import POINTER, sizeof, cast, create_string_buffer, string_at, create_unicode_buffer, wstring_at, memmove, memset, c_char_p, c_byte, c_ubyte, c_wchar
label_desc: Use image node_id 6 for calling the MemFunctionsTest obj's underlying member method code with example usage: obj.test_wstring_at() without return types