Method _test_around_boundary

Lib/test/test_mmap.py:1270–1276

(self, boundary)

    # Issue 11277: mmap() with large (~4 GiB) sparse files crashes on OS X.

    def _test_around_boundary(self, boundary):
        tail = b'  DEARdear  '
        start = boundary - len(tail) // 2
        end = start + len(tail)
        with self._make_test_file(start, tail) as f:
            with mmap.mmap(f.fileno(), 0, access=mmap.ACCESS_READ) as m:
                self.assertEqual(m[start:end], tail)

    @unittest.skipUnless(sys.maxsize > _4G, "test cannot run on 32-bit systems")
    def test_around_2GB(self):