def METHOD_NAME(self):
    # the same test as in scipy.signal
    x = signal.firls(101, [0, 0.01, 0.99, 1], [1, 1, 0, 0])
    w, h = signal.freqz(x, fs=2.)
    mask = w < 0.01
    assert mask.sum() > 3
    testing.assert_allclose(cupy.abs(h[mask]), 1., atol=1e-4)
    mask = w > 0.99
    assert mask.sum() > 3
    testing.assert_allclose(cupy.abs(h[mask]), 0., atol=1e-4)