code: def test_contours_categorical_color(self):
      path = Contours(
          [
              {("x", "y"): np.random.rand(10, 2), "z": cat}
              for cat in ("B", "A", "B")
          ],
          vdims="z",
      ).opts(color_index="z")
      plot = mpl_renderer.get_plot(path)
      artist = plot.handles["artist"]
      self.assertEqual(
          np.asarray(artist.get_array()), np.array([0, 1, 0])
      )
      self.assertEqual(artist.get_clim(), (0, 1))
  
imports: import numpy
  import pytest
  from holoviews.core import NdOverlay
  from holoviews.core.options import AbbreviatedException
  from holoviews.core.spaces import HoloMap
  from holoviews.element import Contours, Path, Polygons
  from .test_plot import TestMPLPlot, mpl_renderer
label_desc: Use image node_id 1 for calling the TestContoursPlot obj's underlying member method code with example usage: obj.test_contours_categorical_color() without return types