class_docstr: Test OneHotFeaturizer.
docstr: Test one hot encoding with max_length.
code: def test_onehot_featurizer_arbitrary_with_max_length(self):
      """
      Test one hot encoding with max_length.
      """
      string = "abcdefghijklmnopqrstuvwxyzvewqmc"
      charset = "abcdefghijklmnopqrstuvwxyz"
      length = len(charset) + 1
      featurizer = OneHotFeaturizer(charset, max_length=120)
      feature = featurizer([string])
      assert feature.shape == (1, 120, length)
      # untranform
      undo_string = featurizer.untransform(feature[0])
      assert string == undo_string
  
file_path: deepchem/deepchem/feat/tests/test_one_hot_featurizer.py
imports: import unittest
  import numpy
  from deepchem.feat import OneHotFeaturizer
  from deepchem.feat.molecule_featurizers.one_hot_featurizer import ZINC_CHARSET
label_desc: Use image node_id 3 for calling the TestOneHotFeaturizer obj's underlying member method code with example usage: obj.test_onehot_featurizer_arbitrary_with_max_length() without return types