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67 lines
2.1 KiB
Python
67 lines
2.1 KiB
Python
import ctypes
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from unittest import mock
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from django.contrib.gis.ptr import CPointerBase
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from django.test import SimpleTestCase
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class CPointerBaseTests(SimpleTestCase):
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def test(self):
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destructor_mock = mock.Mock()
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class NullPointerException(Exception):
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pass
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class FakeGeom1(CPointerBase):
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null_ptr_exception_class = NullPointerException
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class FakeGeom2(FakeGeom1):
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ptr_type = ctypes.POINTER(ctypes.c_float)
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destructor = destructor_mock
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fg1 = FakeGeom1()
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fg2 = FakeGeom2()
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# These assignments are OK. None is allowed because it's equivalent
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# to the NULL pointer.
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fg1.ptr = fg1.ptr_type()
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fg1.ptr = None
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fg2.ptr = fg2.ptr_type(ctypes.c_float(5.23))
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fg2.ptr = None
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# Because pointers have been set to NULL, an exception is raised on
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# access. Raising an exception is preferable to a segmentation fault
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# that commonly occurs when a C method is given a NULL reference.
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for fg in (fg1, fg2):
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with self.assertRaises(NullPointerException):
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fg.ptr
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# Anything that's either not None or the acceptable pointer type
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# results in a TypeError when trying to assign it to the `ptr` property.
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# Thus, memory addresses (integers) and pointers of the incorrect type
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# (in `bad_ptrs`) aren't allowed.
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bad_ptrs = (5, ctypes.c_char_p(b'foobar'))
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for bad_ptr in bad_ptrs:
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for fg in (fg1, fg2):
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with self.assertRaisesMessage(TypeError, 'Incompatible pointer type'):
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fg.ptr = bad_ptr
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# Object can be deleted without a destructor set.
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fg = FakeGeom1()
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fg.ptr = fg.ptr_type(1)
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del fg
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# A NULL pointer isn't passed to the destructor.
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fg = FakeGeom2()
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fg.ptr = None
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del fg
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self.assertFalse(destructor_mock.called)
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# The destructor is called if set.
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fg = FakeGeom2()
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ptr = fg.ptr_type(ctypes.c_float(1.))
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fg.ptr = ptr
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del fg
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destructor_mock.assert_called_with(ptr)
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