code: def test_dtypes_nonstandard(self, dtype):
      x = random(30).astype(dtype)
      out_dtypes = {
          np.float16: np.complex64,
          np.longdouble: np.clongdouble,
      }
      x_complex = x.astype(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
      assert_array_almost_equal(res_fft, x_complex)
      assert_array_almost_equal(res_rfft, x)
      assert_array_almost_equal(res_hfft, x)
      assert res_fft.dtype == x_complex.dtype
      assert res_rfft.dtype == np.result_type(np.float32, x.dtype)
      assert res_hfft.dtype == np.result_type(np.float32, x.dtype)
  
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 26 for calling the TestFFT1D obj's underlying member method code with example usage: obj.test_dtypes_nonstandard(dtype) without return types