code: def test_empty(self):
      # I had problems with these
      #
      # Although these are pathological cases: Empty Structures!
      class X(Structure):
          _fields_ = []
  
      class Y(Union):
          _fields_ = []
  
      # Is this really the correct alignment, or should it be 0?
      self.assertTrue(alignment(X) == alignment(Y) == 1)
      self.assertTrue(sizeof(X) == sizeof(Y) == 0)
  
      class XX(Structure):
          _fields_ = [("a", X), ("b", X)]
  
      self.assertEqual(alignment(XX), 1)
      self.assertEqual(sizeof(XX), 0)
  
imports: import _ctypes_test
  from platform import architecture
  import struct
  import sys
  import unittest
  from ctypes import CDLL, Array, Structure, Union, POINTER, sizeof, byref, alignment, c_void_p, c_char, c_wchar, c_byte, c_ubyte, c_uint8, c_uint16, c_uint32, c_short, c_ushort, c_int, c_uint, c_long, c_ulong, c_longlong, c_ulonglong, c_float, c_double
  from ctypes.util import find_library
  from struct import calcsize
  from collections import namedtuple
  from test import support
  from ._support import _CData, PyCStructType, Py_TPFLAGS_DISALLOW_INSTANTIATION, Py_TPFLAGS_IMMUTABLETYPE
label_desc: Use image node_id 6 for calling the StructureTestCase obj's underlying member method code with example usage: obj.test_empty() without return types