'Use a list of coefficients instead of a poly1d.'

def test_sweep_poly_cubic3(self):

    p = [2.0, 1.0, 0.0, (-2.0)]
    t = np.linspace(0, 2.0, 10000)
    phase = waveforms._sweep_poly_phase(t, p)
    (tf, f) = compute_frequency(t, phase)
    expected = np.poly1d(p)(tf)
    abserr = np.max(np.abs((f - expected)))
    assert_((abserr < 1e-06))
