'``allocated_size`` returns next multiple of
``allocation_unit`` if ``requested_size`` is not a multiple of
``allocation_unit``.'

def test_round_up(self):

    requested_size = (self.allocation_unit + 1)
    expected_size = (self.allocation_unit * 2)
    self.assertEqual(expected_size, allocated_size(self.allocation_unit, requested_size))
