class_docstr: Test the PCA visualizer
class_docstr_tok: ["Test","the","PCA","visualizer"]
docstr: Test single target.
docstr_tok: ["Test","single","target","."]
code: def test_single(self):
      """
      Test single target.
      """
      visualizer = PCA(random_state=1998)
      visualizer.fit(self.continuous.X)
      visualizer.transform(self.continuous.X)
      assert not hasattr(visualizer, "classes_")
      assert not hasattr(visualizer, "range_")
      self.assert_images_similar(visualizer)
  
imports: import sys
  import pytest
  import numpy
  import numpy.testing
  from unittest import mock
  from tests.base import VisualTestCase, IS_WINDOWS_OR_CONDA
  from yellowbrick.features.pca import *
  from yellowbrick.exceptions import YellowbrickError, NotFitted
label_desc: Use image node_id 1 for calling the TestPCA obj's underlying member method code with example usage: obj.test_single() without return types