class_docstr: Test DecisionBoundariesVisualizer
class_docstr_tok: ["Test","DecisionBoundariesVisualizer"]
docstr: Test fit when features is None
docstr_tok: ["Test","fit","when","features","is","None"]
code: def test_fit_features_assignment_None(self):
      """
      Test fit when features is None
      """
      model = neighbors.KNeighborsClassifier(3)
      viz = DecisionBoundariesVisualizer(model)
      assert viz.features_ is None
      fitted_viz = viz.fit(X_two_cols, y=y)
      assert fitted_viz.features_ == ["Feature One", "Feature Two"]
  
imports: import sys
  import pytest
  import numpy
  from unittest import mock
  from tests.base import VisualTestCase
  from yellowbrick.contrib.classifier import *
  from yellowbrick.exceptions import YellowbrickTypeError
  from yellowbrick.exceptions import YellowbrickValueError
  from sklearn import datasets
  from sklearn import neighbors
  from sklearn import naive_bayes
label_desc: Use image node_id 8 for calling the TestDecisionBoundariesVisualizer obj's underlying member method code with example usage: obj.test_fit_features_assignment_None() without return types