docstr: Test deleting a cache object ends cache thread.
          
docstr_tok: ["Test","deleting","a","cache","object","ends","cache","thread","."]
code: def test_delete_cache_object(self):
      """Test deleting a cache object ends cache thread."""
      # Firstly make sure we've exited any lingering threads from other
      # tests.
      time.sleep(0.25)
      self.assertTrue(_check_n_cache_threads_running() == 0)
  
      _cache = interfaces.cache._Cache()
      time.sleep(0.25)
      self.assertTrue(_check_n_cache_threads_running() == 1)
  
      del _cache
      time.sleep(0.25)
      self.assertTrue(_check_n_cache_threads_running() == 0)
  
imports: import copy
  import sys
  from pyfftw import interfaces, builders
  import pyfftw
  import numpy
  import numpy
  import unittest
  from .test_pyfftw_base import run_test_suites, miss
  from .test_pyfftw_numpy_interface import InterfacesNumpyFFTTestFFT
  import threading
  import time
  import os
  import hashlib
label_desc: Use image node_id 2 for calling the CacheTest obj's underlying member method code with example usage: obj.test_delete_cache_object() without return types