code: def test_definition(self, rdt, type, fftwdata_size, reference_data):
      x, yr, dt = fftw_dct_ref(type, fftwdata_size, rdt, reference_data)
      y = dct(x, type=type)
      assert_equal(y.dtype, dt)
      dec = dec_map[(dct, rdt, type)]
      assert_allclose(y, yr, rtol=0.0, atol=np.max(yr) * 10 ** (-dec))
  
imports: from os.path import join, dirname
  from typing import Callable, Union
  import numpy
  from numpy.testing import assert_array_almost_equal, assert_equal, assert_allclose
  import pytest
  from pytest import raises
  from scipy.fft._pocketfft.realtransforms import dct, idct, dst, idst, dctn, idctn, dstn, idstn
label_desc: Use image node_id 1 for calling the TestDCT obj's underlying member method code with example usage: obj.test_definition(rdt, type, fftwdata_size, reference_data) without return types