'1 set 1D x, 1pset'

def test_linear_fitter_1set(self):

    expected = np.array([0, 1, 1, 1])
    p1 = models.Polynomial1D(3)
    p1.parameters = [0, 1, 1, 1]
    y1 = p1(self.x1)
    pfit = fitting.LinearLSQFitter()
    model = pfit(p1, self.x1, y1)
    assert_allclose(model.parameters, expected, atol=(10 ** (-7)))
