class_docstr: Test FeatureVisualizer base class
class_docstr_tok: ["Test","FeatureVisualizer","base","class"]
docstr: Ensure transformer is just a passthrough
code: def test_transform_returns_unmodified(self):
      """
      Ensure transformer is just a passthrough
      """
      X, y = self.discrete
      visualizer = FeatureVisualizer().fit(X, y)
      assert visualizer.transform(X, y) is X
  
imports: import pytest
  import numpy
  import numpy.testing
  from tests.fixtures import Dataset
  from yellowbrick.base import Visualizer
  from yellowbrick.features.base import *
  from sklearn.base import BaseEstimator, TransformerMixin
  from sklearn.datasets import make_classification, make_regression
  from unittest.mock import Mock
label_desc: Use image node_id 2 for calling the TestFeatureVisualizer obj's underlying member method code with example usage: obj.test_transform_returns_unmodified() without return types