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from ctypes import *
import unittest
class X(Structure):
_fields_ = [("a", c_int),
("b", c_int)]
new_was_called = False
def __new__(cls):
result = super().__new__(cls)
result.new_was_called = True
return result
def __init__(self):
self.a = 9
self.b = 12
class Y(Structure):
_fields_ = [("x", X)]
class InitTest(unittest.TestCase):
def test_get(self):
# make sure the only accessing a nested structure
# doesn't call the structure's __new__ and __init__
y = Y()
self.assertEqual((y.x.a, y.x.b), (0, 0))
self.assertEqual(y.x.new_was_called, False)
# But explicitly creating an X structure calls __new__ and __init__, of course.
x = X()
self.assertEqual((x.a, x.b), (9, 12))
self.assertEqual(x.new_was_called, True)
y.x = x
self.assertEqual((y.x.a, y.x.b), (9, 12))
self.assertEqual(y.x.new_was_called, False)
if __name__ == "__main__":
unittest.main()
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