code: def test_file(self):
      cache = FileCache("predict", max_size=2)
  
      self.cache_test(cache)
  
file_path: mindsdb/tests/unit/test_cache.py
imports: import datetime
  import time
  import unittest
  import traceback
  import redis
  import warnings
  import tempfile
  import json
  import os
  import pandas
  from mindsdb.utilities.cache import get_cache, RedisCache, FileCache, dataframe_checksum
label_desc: Use image node_id 3 for calling the TestCashe obj's underlying member method code with example usage: obj.test_file() without return types