code: def test_next_fast_len(self):
      def nums():
          for j in range(1, 1000):
              yield j
          yield 2**5 * 3**5 * 4**5 + 1
  
      for n in nums():
          m = pyfftw.next_fast_len(n)
          msg = "n=%d, m=%d" % (n, m)
  
          assert_(m >= n, msg)
  
          # check regularity
          k = m
          num11 = num13 = 0
          # These factors come from the description in the FFTW3 docs:
          #     http://fftw.org/fftw3_doc/Complex-DFTs.html#Complex-DFTs
          for d in [2, 3, 5, 7, 11, 13]:
              while True:
                  a, b = divmod(k, d)
                  if b == 0:
                      k = a
                      if d in [11, 13]:
                          # only allowed to match 11 or 13 once
                          if num11 > 0 or num13 > 0:
                              break
                          if d == 11:
                              num11 += 1
                          else:
                              num13 += 1
                  else:
                      break
          assert_equal(k, 1, err_msg=msg)
  
file_path: py-fftw/tests/test_pyfftw_utils.py
imports: from .test_pyfftw_base import run_test_suites
  import unittest
  import pyfftw
  import platform
  import os
  from numpy.testing import assert_, assert_equal
label_desc: Use image node_id 2 for calling the NextFastLenTest obj's underlying member method code with example usage: obj.test_next_fast_len() without return types