def METHOD_NAME(self):
    #         (input) (expected output)
    values = [((1, 1), 1),
              ((-1.234, 1), -1),
              ((-1234, 1), -1000),
              ((1600, 1), 2000),
              ((-1600, 1), -2000),
              ((0.0001236, 3), 0.000124),
              ((0, 5), 0),
              ((4.375479375074184e-6, 3), 4.38e-6),
              ]
    for (i, eo) in values:
        o = units.round_significant(*i)
        self.assertEqual(o, eo,
                          u"%f to %d figures = %f should be %f" % (i[0], i[1], o, eo))