code: def test_dtypes(self, dtype, xp):
      x = xp.asarray(random(30), dtype=getattr(xp, dtype))
      out_dtypes = {"float32": xp.complex64, "float64": xp.complex128}
      x_complex = xp.asarray(x, dtype=out_dtypes[dtype])
  
      res_fft = fft.ifft(fft.fft(x))
      res_rfft = fft.irfft(fft.rfft(x))
      res_hfft = fft.hfft(fft.ihfft(x), x.shape[0])
      # Check both numerical results and exact dtype matches
      rtol = {"float32": 1.2e-4, "float64": 1e-8}[dtype]
      xp_assert_close(res_fft, x_complex, rtol=rtol, atol=0)
      xp_assert_close(res_rfft, x, rtol=rtol, atol=0)
      xp_assert_close(res_hfft, x, rtol=rtol, atol=0)
  
imports: import queue
  import threading
  import multiprocessing
  import numpy
  import pytest
  from numpy.random import random
  from numpy.testing import assert_array_almost_equal, assert_allclose
  from pytest import raises
  import scipy.fft
  from scipy.conftest import array_api_compatible, skip_if_array_api_backend
  from scipy._lib._array_api import array_namespace, size, xp_assert_close, xp_assert_equal
label_desc: Use image node_id 27 for calling the TestFFT1D obj's underlying member method code with example usage: obj.test_dtypes(dtype, xp) without return types