def METHOD_NAME(self):
    dll = CDLL(_ctypes_test.__file__)
    for i in range(1, 11):
        fields = [ (f"f{f}", c_char) for f in range(1, i + 1)]
        class S(Structure):
            _fields_ = fields
        f = getattr(dll, f"TestSize{i}")
        f.restype = S
        res = f()
        for i, f in enumerate(fields):
            value = getattr(res, f[0])
            expected = bytes([ord('a') + i])
            self.assertEqual(value, expected)