code: def test_len(runhistory, config1):
      """Test that adding items will increase the length monotonically"""
      assert len(runhistory) == 0
  
      n_items = 5
  
      for i in range(n_items):
          assert len(runhistory) == i
  
          add_item(runhistory, config1, budget=i)
  
          assert len(runhistory) == i + 1
  
      assert len(runhistory) == n_items
  
imports: from __future__ import annotations
  import os
  import pickle
  import tempfile
  import pytest
  from smac.runhistory.runhistory import RunHistory, TrialKey
  from smac.runner.abstract_runner import StatusType
label_desc: Use image node_id 18 for calling a global function with example usage: test_len(runhistory, config1) without return types