code: def test_vectorfield_categorical_color_op(self):
      vectorfield = VectorField(
          [(0, 0, 0, 1, "A"), (0, 1, 0, 1, "B"), (0, 2, 0, 1, "C")],
          vdims=["A", "M", "color"],
      ).opts(color="color")
      plot = mpl_renderer.get_plot(vectorfield)
      artist = plot.handles["artist"]
      self.assertEqual(
          np.asarray(artist.get_array()), np.array([0, 1, 2])
      )
      self.assertEqual(artist.get_clim(), (0, 2))
  
file_path: holoviews/holoviews/tests/plotting/matplotlib/test_vectorfieldplot.py
imports: import numpy
  import pytest
  from holoviews.core.options import AbbreviatedException
  from holoviews.core.spaces import HoloMap
  from holoviews.element import VectorField
  from ..utils import ParamLogStream
  from .test_plot import TestMPLPlot, mpl_renderer
label_desc: Use image node_id 4 for calling the TestVectorFieldPlot obj's underlying member method code with example usage: obj.test_vectorfield_categorical_color_op() without return types