1 from ctypes import * 2 import unittest 3 4 class X(Structure): 5 _fields_ = [("a", c_int), 6 ("b", c_int)] 7 new_was_called = False 8 9 def __new__(cls): 10 result = super(X, cls).__new__(cls) 11 result.new_was_called = True 12 return result 13 14 def __init__(self): 15 self.a = 9 16 self.b = 12 17 18 class Y(Structure): 19 _fields_ = [("x", X)] 20 21 22 class InitTest(unittest.TestCase): 23 def test_get(self): 24 # make sure the only accessing a nested structure 25 # doesn't call the structure's __new__ and __init__ 26 y = Y() 27 self.assertEqual((y.x.a, y.x.b), (0, 0)) 28 self.assertEqual(y.x.new_was_called, False) 29 30 # But explicitly creating an X structure calls __new__ and __init__, of course. 31 x = X() 32 self.assertEqual((x.a, x.b), (9, 12)) 33 self.assertEqual(x.new_was_called, True) 34 35 y.x = x 36 self.assertEqual((y.x.a, y.x.b), (9, 12)) 37 self.assertEqual(y.x.new_was_called, False) 38 39 if __name__ == "__main__": 40 unittest.main() 41