docstr: Test CacheStatsProvider implementation.
docstr_tok: ["Test","CacheStatsProvider","implementation","."]
code: def test_cache_stats_provider(self):
      """Test CacheStatsProvider implementation."""
  
      # Test empty manager
      self.assertEqual([], self.mgr.get_stats())
  
      # Test manager with files
      self.mgr.add_file("session1", FILE_1)
      self.mgr.add_file("session1", FILE_2)
  
      expected = [
          CacheStat(
              category_name="UploadedFileManager",
              cache_name="",
              byte_length=len(FILE_1.data) + len(FILE_2.data),
          ),
      ]
      self.assertEqual(expected, self.mgr.get_stats())
  
file_path: streamlit/lib/tests/streamlit/runtime/uploaded_file_manager_test.py
imports: import unittest
  from streamlit.runtime.memory_uploaded_file_manager import MemoryUploadedFileManager
  from streamlit.runtime.stats import CacheStat
  from streamlit.runtime.uploaded_file_manager import UploadedFileRec
  from tests.exception_capturing_thread import call_on_threads
label_desc: Use image node_id 6 for calling the UploadedFileManagerTest obj's underlying member method code with example usage: obj.test_cache_stats_provider() without return types