code: def test_bond_features_none():
      """
      Test for bond_features() with 'None' input for bond
      """
      f_bond = bond_features(None)
      req_f = list(np.zeros((14,), dtype=int))
      req_f[0] = 1
      assert len(f_bond) == len(req_f)
      assert f_bond == req_f
  
file_path: deepchem/deepchem/feat/tests/test_features_generator_dmpnn.py
imports: from deepchem.feat.molecule_featurizers.dmpnn_featurizer import bond_features, map_reac_to_prod
  from rdkit import Chem
  import pytest
  import numpy
label_desc: Use image node_id 2 for calling a global function with example usage: test_bond_features_none() without return types