test_struct.py 文件源码

def test_pack_into_fn(self):
        test_string = b'Reykjavik rocks, eow!'
        writable_buf = array.array('b', b' '*100)
        fmt = '21s'
        pack_into = lambda *args: struct.pack_into(fmt, *args)

        # Test without offset.
        pack_into(writable_buf, 0, test_string)
        from_buf = writable_buf.tobytes()[:len(test_string)]
        self.assertEqual(from_buf, test_string)

        # Test with offset.
        pack_into(writable_buf, 10, test_string)
        from_buf = writable_buf.tobytes()[:len(test_string)+10]
        self.assertEqual(from_buf, test_string[:10] + test_string)

        # Go beyond boundaries.
        small_buf = array.array('b', b' '*10)
        self.assertRaises((ValueError, struct.error), pack_into, small_buf, 0,
                          test_string)
        self.assertRaises((ValueError, struct.error), pack_into, small_buf, 2,
                          test_string)