code: def test_armafft(ar, ma):
      # test other methods
      nfreq = 20
      w = np.linspace(0, np.pi, nfreq, endpoint=False)
  
      arma = ArmaFft(ar, ma, 20)
      ac1 = arma.invpowerspd(1024)[:10]
      ac2 = arma.acovf(10)[:10]
      assert_allclose(
          ac1,
          ac2,
          atol=1e-15,
          err_msg="acovf not equal for {}, {}".format(ar, ma),
      )
  
imports: from statsmodels.compat.pandas import QUARTER_END
  import datetime
  import numpy
  from numpy.testing import assert_, assert_allclose, assert_almost_equal, assert_array_almost_equal, assert_equal, assert_raises
  import pandas
  import pytest
  from statsmodels.sandbox.tsa.fftarma import ArmaFft
  from statsmodels.tsa.arima.model import ARIMA
  from statsmodels.tsa.arima_process import ArmaProcess, arma_acf, arma_acovf, arma_generate_sample, arma_impulse_response, index2lpol, lpol2index, lpol_fiar, lpol_fima
  from statsmodels.tsa.tests.results import results_arma_acf
  from statsmodels.tsa.tests.results.results_process import armarep
label_desc: Use image node_id 11 for calling a global function with example usage: test_armafft(ar, ma) without return types