text: import unittest
  from ctypes import *
  from ctypes.test import need_symbol
  from struct import calcsize
  import _ctypes_test
  import test.support
  
  class SubclassesTest(unittest.TestCase):
      def test_subclass(self):
          class X(Structure):
              _fields_ = [("a", c_int)]
  
          class Y(X):
              _fields_ = [("b", c_int)]
  
          class Z(X):
              pass
  
          self.assertEqual(sizeof(X), sizeof(c_int))
          self.assertEqual(sizeof(Y), sizeof(c_int)*2)
          self.assertEqual(sizeof(Z), sizeof(c_int))
          self.assertEqual(X._fields_, [("a", c_int)])
          self.assertEqual(Y._fields_, [("b", c_int)])
          self.assertEqual(Z._fields_, [("a", c_int)])
  
      def test_subclass_delayed(self):
          class X(Structure):
              pass
          self.assertEqual(sizeof(X), 0)
          X._fields_ = [("a", c_int)]
  
          class Y(X):
              pass
          self.assertEqual(sizeof(Y), sizeof(X))
          Y._fields_ = [("b", c_int)]
  
          class Z(X):
              pass
  
          self.assertEqual(sizeof(X), sizeof(c_int))
          self.assertEqual(sizeof(Y), sizeof(c_int)*2)
          self.assertEqual(sizeof(Z), sizeof(c_int))
          self.assertEqual(X._fields_, [("a", c_int)])
          self.assertEqual(Y._fields_, [("b", c_int)])
          self.assertEqual(Z._fields_, [("a", c_int)])
  
  class StructureTestCase(unittest.TestCase):
      formats = {"c": c_char,
                 "b": c_byte,
                 "B": c_ubyte,
                 "h": c_short,
                 "H": c_ushort,
                 "i": c_int,
                 "I": c_uint,
                 "l": c_long,
                 "L": c_ulong,
                 "q": c_longlong,
                 "Q": c_ulonglong,
                 "f": c_float,
                 "d": c_double,
                 }
  
      def test_simple_structs(self):
          for code, tp in self.formats.items():
              class X(Structure):
                  _fields_ = [("x", c_char),
                              ("y", tp)]
              self.assertEqual((sizeof(X), code),
                                   (calcsize("c%c0%c" % (code, code)), code))
  
      def test_unions(self):
          for code, tp in self.formats.items():
              class X(Union):
                  _fields_ = [("x", c_char),
                              ("y", tp)]
              self.assertEqual((sizeof(X), code),
                                   (calcsize("%c" % (code)), code))
  
      def test_struct_alignment(self):
          class X(Structure):
              _fields_ = [("x", c_char * 3)]
          self.assertEqual(alignment(X), calcsize("s"))
          self.assertEqual(sizeof(X), calcsize("3s"))
  
          class Y(Structure):
              _fields_ = [("x", c_char * 3),
                          ("y", c_int)]
          self.assertEqual(alignment(Y), alignment(c_int))
          self.assertEqual(sizeof(Y), calcsize("3si"))
  
          class SI(Structure):
              _fields_ = [("a", X),
                          ("b", Y)]
          self.assertEqual(alignment(SI), max(alignment(Y), alignment(X)))
          self.assertEqual(sizeof(SI), calcsize("3s0i 3si 0i"))
  
          class IS(Structure):
              _fields_ = [("b", Y),
                          ("a", X)]
  
          self.assertEqual(alignment(SI), max(alignment(X), alignment(Y)))
          self.assertEqual(sizeof(IS), calcsize("3si 3s 0i"))
  
          class XX(Structure):
              _fields_ = [("a", X),
                          ("b", X)]
          self.assertEqual(alignment(XX), alignment(X))
          self.assertEqual(sizeof(XX), calcsize("3s 3s 0s"))
  
      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)
  
      def test_fields(self):
          # test the offset and size attributes of Structure/Unoin fields.
          class X(Structure):
              _fields_ = [("x", c_int),
                          ("y", c_char)]
  
          self.assertEqual(X.x.offset, 0)
          self.assertEqual(X.x.size, sizeof(c_int))
  
          self.assertEqual(X.y.offset, sizeof(c_int))
          self.assertEqual(X.y.size, sizeof(c_char))
  
          # readonly
          self.assertRaises((TypeError, AttributeError), setattr, X.x, "offset", 92)
          self.assertRaises((TypeError, AttributeError), setattr, X.x, "size", 92)
  
          class X(Union):
              _fields_ = [("x", c_int),
                          ("y", c_char)]
  
          self.assertEqual(X.x.offset, 0)
          self.assertEqual(X.x.size, sizeof(c_int))
  
          self.assertEqual(X.y.offset, 0)
          self.assertEqual(X.y.size, sizeof(c_char))
  
          # readonly
          self.assertRaises((TypeError, AttributeError), setattr, X.x, "offset", 92)
          self.assertRaises((TypeError, AttributeError), setattr, X.x, "size", 92)
  
          # XXX Should we check nested data types also?
          # offset is always relative to the class...
  
      def test_packed(self):
          class X(Structure):
              _fields_ = [("a", c_byte),
                          ("b", c_longlong)]
              _pack_ = 1
  
          self.assertEqual(sizeof(X), 9)
          self.assertEqual(X.b.offset, 1)
  
          class X(Structure):
              _fields_ = [("a", c_byte),
                          ("b", c_longlong)]
              _pack_ = 2
          self.assertEqual(sizeof(X), 10)
          self.assertEqual(X.b.offset, 2)
  
          import struct
          longlong_size = struct.calcsize("q")
          longlong_align = struct.calcsize("bq") - longlong_size
  
          class X(Structure):
              _fields_ = [("a", c_byte),
                          ("b", c_longlong)]
              _pack_ = 4
          self.assertEqual(sizeof(X), min(4, longlong_align) + longlong_size)
          self.assertEqual(X.b.offset, min(4, longlong_align))
  
          class X(Structure):
              _fields_ = [("a", c_byte),
                          ("b", c_longlong)]
              _pack_ = 8
  
          self.assertEqual(sizeof(X), min(8, longlong_align) + longlong_size)
          self.assertEqual(X.b.offset, min(8, longlong_align))
  
  
          d = {"_fields_": [("a", "b"),
                            ("b", "q")],
               "_pack_": -1}
          self.assertRaises(ValueError, type(Structure), "X", (Structure,), d)
  
      @test.support.cpython_only
      def test_packed_c_limits(self):
          # Issue 15989
          import _testcapi
          d = {"_fields_": [("a", c_byte)],
               "_pack_": _testcapi.INT_MAX + 1}
          self.assertRaises(ValueError, type(Structure), "X", (Structure,), d)
          d = {"_fields_": [("a", c_byte)],
               "_pack_": _testcapi.UINT_MAX + 2}
          self.assertRaises(ValueError, type(Structure), "X", (Structure,), d)
  
      def test_initializers(self):
          class Person(Structure):
              _fields_ = [("name", c_char*6),
                          ("age", c_int)]
  
          self.assertRaises(TypeError, Person, 42)
          self.assertRaises(ValueError, Person, b"asldkjaslkdjaslkdj")
          self.assertRaises(TypeError, Person, "Name", "HI")
  
          # short enough
          self.assertEqual(Person(b"12345", 5).name, b"12345")
          # exact fit
          self.assertEqual(Person(b"123456", 5).name, b"123456")
          # too long
          self.assertRaises(ValueError, Person, b"1234567", 5)
  
      def test_conflicting_initializers(self):
          class POINT(Structure):
              _fields_ = [("phi", c_float), ("rho", c_float)]
          # conflicting positional and keyword args
          self.assertRaisesRegex(TypeError, "phi", POINT, 2, 3, phi=4)
          self.assertRaisesRegex(TypeError, "rho", POINT, 2, 3, rho=4)
  
          # too many initializers
          self.assertRaises(TypeError, POINT, 2, 3, 4)
  
      def test_keyword_initializers(self):
          class POINT(Structure):
              _fields_ = [("x", c_int), ("y", c_int)]
          pt = POINT(1, 2)
          self.assertEqual((pt.x, pt.y), (1, 2))
  
          pt = POINT(y=2, x=1)
          self.assertEqual((pt.x, pt.y), (1, 2))
  
      def test_invalid_field_types(self):
          class POINT(Structure):
              pass
          self.assertRaises(TypeError, setattr, POINT, "_fields_", [("x", 1), ("y", 2)])
  
      def test_invalid_name(self):
          # field name must be string
          def declare_with_name(name):
              class S(Structure):
                  _fields_ = [(name, c_int)]
  
          self.assertRaises(TypeError, declare_with_name, b"x")
  
      def test_intarray_fields(self):
          class SomeInts(Structure):
              _fields_ = [("a", c_int * 4)]
  
          # can use tuple to initialize array (but not list!)
          self.assertEqual(SomeInts((1, 2)).a[:], [1, 2, 0, 0])
          self.assertEqual(SomeInts((1, 2)).a[::], [1, 2, 0, 0])
          self.assertEqual(SomeInts((1, 2)).a[::-1], [0, 0, 2, 1])
          self.assertEqual(SomeInts((1, 2)).a[::2], [1, 0])
          self.assertEqual(SomeInts((1, 2)).a[1:5:6], [2])
          self.assertEqual(SomeInts((1, 2)).a[6:4:-1], [])
          self.assertEqual(SomeInts((1, 2, 3, 4)).a[:], [1, 2, 3, 4])
          self.assertEqual(SomeInts((1, 2, 3, 4)).a[::], [1, 2, 3, 4])
          # too long
          # XXX Should raise ValueError?, not RuntimeError
          self.assertRaises(RuntimeError, SomeInts, (1, 2, 3, 4, 5))
  
      def test_nested_initializers(self):
          # test initializing nested structures
          class Phone(Structure):
              _fields_ = [("areacode", c_char*6),
                          ("number", c_char*12)]
  
          class Person(Structure):
              _fields_ = [("name", c_char * 12),
                          ("phone", Phone),
                          ("age", c_int)]
  
          p = Person(b"Someone", (b"1234", b"5678"), 5)
  
          self.assertEqual(p.name, b"Someone")
          self.assertEqual(p.phone.areacode, b"1234")
          self.assertEqual(p.phone.number, b"5678")
          self.assertEqual(p.age, 5)
  
      @need_symbol('c_wchar')
      def test_structures_with_wchar(self):
          class PersonW(Structure):
              _fields_ = [("name", c_wchar * 12),
                          ("age", c_int)]
  
          p = PersonW("Someone \xe9")
          self.assertEqual(p.name, "Someone \xe9")
  
          self.assertEqual(PersonW("1234567890").name, "1234567890")
          self.assertEqual(PersonW("12345678901").name, "12345678901")
          # exact fit
          self.assertEqual(PersonW("123456789012").name, "123456789012")
          #too long
          self.assertRaises(ValueError, PersonW, "1234567890123")
  
      def test_init_errors(self):
          class Phone(Structure):
              _fields_ = [("areacode", c_char*6),
                          ("number", c_char*12)]
  
          class Person(Structure):
              _fields_ = [("name", c_char * 12),
                          ("phone", Phone),
                          ("age", c_int)]
  
          cls, msg = self.get_except(Person, b"Someone", (1, 2))
          self.assertEqual(cls, RuntimeError)
          self.assertEqual(msg,
                               "(Phone) <class 'TypeError'>: "
                               "expected bytes, int found")
  
          cls, msg = self.get_except(Person, b"Someone", (b"a", b"b", b"c"))
          self.assertEqual(cls, RuntimeError)
          if issubclass(Exception, object):
              self.assertEqual(msg,
                                   "(Phone) <class 'TypeError'>: too many initializers")
          else:
              self.assertEqual(msg, "(Phone) TypeError: too many initializers")
  
      def test_huge_field_name(self):
          # issue12881: segfault with large structure field names
          def create_class(length):
              class S(Structure):
                  _fields_ = [('x' * length, c_int)]
  
          for length in [10 ** i for i in range(0, 8)]:
              try:
                  create_class(length)
              except MemoryError:
                  # MemoryErrors are OK, we just don't want to segfault
                  pass
  
      def get_except(self, func, *args):
          try:
              func(*args)
          except Exception as detail:
              return detail.__class__, str(detail)
  
      @unittest.skip('test disabled')
      def test_subclass_creation(self):
          meta = type(Structure)
          # same as 'class X(Structure): pass'
          # fails, since we need either a _fields_ or a _abstract_ attribute
          cls, msg = self.get_except(meta, "X", (Structure,), {})
          self.assertEqual((cls, msg),
                  (AttributeError, "class must define a '_fields_' attribute"))
  
      def test_abstract_class(self):
          class X(Structure):
              _abstract_ = "something"
          # try 'X()'
          cls, msg = self.get_except(eval, "X()", locals())
          self.assertEqual((cls, msg), (TypeError, "abstract class"))
  
      def test_methods(self):
  ##        class X(Structure):
  ##            _fields_ = []
  
          self.assertIn("in_dll", dir(type(Structure)))
          self.assertIn("from_address", dir(type(Structure)))
          self.assertIn("in_dll", dir(type(Structure)))
  
      def test_positional_args(self):
          # see also http://bugs.python.org/issue5042
          class W(Structure):
              _fields_ = [("a", c_int), ("b", c_int)]
          class X(W):
              _fields_ = [("c", c_int)]
          class Y(X):
              pass
          class Z(Y):
              _fields_ = [("d", c_int), ("e", c_int), ("f", c_int)]
  
          z = Z(1, 2, 3, 4, 5, 6)
          self.assertEqual((z.a, z.b, z.c, z.d, z.e, z.f),
                           (1, 2, 3, 4, 5, 6))
          z = Z(1)
          self.assertEqual((z.a, z.b, z.c, z.d, z.e, z.f),
                           (1, 0, 0, 0, 0, 0))
          self.assertRaises(TypeError, lambda: Z(1, 2, 3, 4, 5, 6, 7))
  
      def test_pass_by_value(self):
          # This should mirror the structure in Modules/_ctypes/_ctypes_test.c
          class X(Structure):
              _fields_ = [
                  ('first', c_ulong),
                  ('second', c_ulong),
                  ('third', c_ulong),
              ]
  
          s = X()
          s.first = 0xdeadbeef
          s.second = 0xcafebabe
          s.third = 0x0bad1dea
          dll = CDLL(_ctypes_test.__file__)
          func = dll._testfunc_large_struct_update_value
          func.argtypes = (X,)
          func.restype = None
          func(s)
          self.assertEqual(s.first, 0xdeadbeef)
          self.assertEqual(s.second, 0xcafebabe)
          self.assertEqual(s.third, 0x0bad1dea)
  
  class PointerMemberTestCase(unittest.TestCase):
  
      def test(self):
          # a Structure with a POINTER field
          class S(Structure):
              _fields_ = [("array", POINTER(c_int))]
  
          s = S()
          # We can assign arrays of the correct type
          s.array = (c_int * 3)(1, 2, 3)
          items = [s.array[i] for i in range(3)]
          self.assertEqual(items, [1, 2, 3])
  
          # The following are bugs, but are included here because the unittests
          # also describe the current behaviour.
          #
          # This fails with SystemError: bad arg to internal function
          # or with IndexError (with a patch I have)
  
          s.array[0] = 42
  
          items = [s.array[i] for i in range(3)]
          self.assertEqual(items, [42, 2, 3])
  
          s.array[0] = 1
  
  ##        s.array[1] = 42
  
          items = [s.array[i] for i in range(3)]
          self.assertEqual(items, [1, 2, 3])
  
      def test_none_to_pointer_fields(self):
          class S(Structure):
              _fields_ = [("x", c_int),
                          ("p", POINTER(c_int))]
  
          s = S()
          s.x = 12345678
          s.p = None
          self.assertEqual(s.x, 12345678)
  
  class TestRecursiveStructure(unittest.TestCase):
      def test_contains_itself(self):
          class Recursive(Structure):
              pass
  
          try:
              Recursive._fields_ = [("next", Recursive)]
          except AttributeError as details:
              self.assertIn("Structure or union cannot contain itself",
                            str(details))
          else:
              self.fail("Structure or union cannot contain itself")
  
  
      def test_vice_versa(self):
          class First(Structure):
              pass
          class Second(Structure):
              pass
  
          First._fields_ = [("second", Second)]
  
          try:
              Second._fields_ = [("first", First)]
          except AttributeError as details:
              self.assertIn("_fields_ is final", str(details))
          else:
              self.fail("AttributeError not raised")
  
  if __name__ == '__main__':
      unittest.main()
  