class_docstr: Test RdkitGridFeaturizer class defined in rdkit_grid_featurizer module.
code: def test_default_featurizer(self):
      # test if default parameters work
      featurizer = RdkitGridFeaturizer()
      self.assertIsInstance(featurizer, RdkitGridFeaturizer)
      feature_tensor = featurizer.featurize(
          [(self.ligand_file, self.protein_file)]
      )
      self.assertIsInstance(feature_tensor, np.ndarray)
  
file_path: deepchem/deepchem/feat/tests/test_rdkit_grid_features.py
imports: import os
  import unittest
  import numpy
  from deepchem.feat import RdkitGridFeaturizer
label_desc: Use image node_id 2 for calling the TestRdkitGridFeaturizer obj's underlying member method code with example usage: obj.test_default_featurizer() without return types