1 import unittest 2 from ctypes import * 3 4 class StructFieldsTestCase(unittest.TestCase): 5 # Structure/Union classes must get 'finalized' sooner or 6 # later, when one of these things happen: 7 # 8 # 1. _fields_ is set. 9 # 2. An instance is created. 10 # 3. The type is used as field of another Structure/Union. 11 # 4. The type is subclassed 12 # 13 # When they are finalized, assigning _fields_ is no longer allowed. 14 15 def test_1_A(self): 16 class X(Structure): 17 pass 18 self.assertEqual(sizeof(X), 0) # not finalized 19 X._fields_ = [] # finalized 20 self.assertRaises(AttributeError, setattr, X, "_fields_", []) 21 22 def test_1_B(self): 23 class X(Structure): 24 _fields_ = [] # finalized 25 self.assertRaises(AttributeError, setattr, X, "_fields_", []) 26 27 def test_2(self): 28 class X(Structure): 29 pass 30 X() 31 self.assertRaises(AttributeError, setattr, X, "_fields_", []) 32 33 def test_3(self): 34 class X(Structure): 35 pass 36 class Y(Structure): 37 _fields_ = [("x", X)] # finalizes X 38 self.assertRaises(AttributeError, setattr, X, "_fields_", []) 39 40 def test_4(self): 41 class X(Structure): 42 pass 43 class Y(X): 44 pass 45 self.assertRaises(AttributeError, setattr, X, "_fields_", []) 46 Y._fields_ = [] 47 self.assertRaises(AttributeError, setattr, X, "_fields_", []) 48 49 if __name__ == "__main__": 50 unittest.main() 51
