/Lib/ctypes/test/test_values.py

 1"""
 2A testcase which accesses *values* in a dll.
 3"""
 4
 5import unittest
 6from ctypes import *
 7
 8import _ctypes_test
 9
10class ValuesTestCase(unittest.TestCase):
11
12    def test_an_integer(self):
13        ctdll = CDLL(_ctypes_test.__file__)
14        an_integer = c_int.in_dll(ctdll, "an_integer")
15        x = an_integer.value
16        self.failUnlessEqual(x, ctdll.get_an_integer())
17        an_integer.value *= 2
18        self.failUnlessEqual(x*2, ctdll.get_an_integer())
19
20    def test_undefined(self):
21        ctdll = CDLL(_ctypes_test.__file__)
22        self.assertRaises(ValueError, c_int.in_dll, ctdll, "Undefined_Symbol")
23
24    class Win_ValuesTestCase(unittest.TestCase):
25        """This test only works when python itself is a dll/shared library"""
26
27        def test_optimizeflag(self):
28            # This test accesses the Py_OptimizeFlag intger, which is
29            # exported by the Python dll.
30
31            # It's value is set depending on the -O and -OO flags:
32            # if not given, it is 0 and __debug__ is 1.
33            # If -O is given, the flag is 1, for -OO it is 2.
34            # docstrings are also removed in the latter case.
35            opt = c_int.in_dll(pydll, "Py_OptimizeFlag").value
36            if __debug__:
37                self.failUnlessEqual(opt, 0)
38            elif ValuesTestCase.__doc__ is not None:
39                self.failUnlessEqual(opt, 1)
40            else:
41                self.failUnlessEqual(opt, 2)
42
43        def test_frozentable(self):
44            # Python exports a PyImport_FrozenModules symbol. This is a
45            # pointer to an array of struct _frozen entries.  The end of the
46            # array is marked by an entry containing a NULL name and zero
47            # size.
48
49            # In standard Python, this table contains a __hello__
50            # module, and a __phello__ package containing a spam
51            # module.
52            class struct_frozen(Structure):
53                _fields_ = [("name", c_char_p),
54                            ("code", POINTER(c_ubyte)),
55                            ("size", c_int)]
56            FrozenTable = POINTER(struct_frozen)
57
58            ft = FrozenTable.in_dll(pydll, "PyImport_FrozenModules")
59            # ft is a pointer to the struct_frozen entries:
60            items = []
61            for entry in ft:
62                # This is dangerous. We *can* iterate over a pointer, but
63                # the loop will not terminate (maybe with an access
64                # violation;-) because the pointer instance has no size.
65                if entry.name is None:
66                    break
67                items.append((entry.name, entry.size))
68            import sys
69            if sys.version_info[:2] >= (2, 3):
70                expected = [("__hello__", 104), ("__phello__", -104), ("__phello__.spam", 104)]
71            else:
72                expected = [("__hello__", 100), ("__phello__", -100), ("__phello__.spam", 100)]
73            self.failUnlessEqual(items, expected)
74
75            from ctypes import _pointer_type_cache
76            del _pointer_type_cache[struct_frozen]
77
78        def test_undefined(self):
79            self.assertRaises(ValueError, c_int.in_dll, pydll, "Undefined_Symbol")
80
81if __name__ == '__main__':
82    unittest.main()