code: def test_label_linear_color_op(self):
      labels = Labels(
          [(0, 0, 0), (0, 1, 1), (0, 2, 2)], vdims="color"
      ).opts(text_color="color")
      plot = bokeh_renderer.get_plot(labels)
      cds = plot.handles["cds"]
      glyph = plot.handles["glyph"]
      cmapper = plot.handles["text_color_color_mapper"]
      self.assertTrue(cmapper, LinearColorMapper)
      self.assertEqual(cmapper.low, 0)
      self.assertEqual(cmapper.high, 2)
      self.assertEqual(cds.data["text_color"], np.array([0, 1, 2]))
      self.assertEqual(
          property_to_dict(glyph.text_color),
          {"field": "text_color", "transform": cmapper},
      )
  
imports: import numpy
  from bokeh.models import CategoricalColorMapper, LinearColorMapper
  from holoviews.core.dimension import Dimension
  from holoviews.core.options import Cycle
  from holoviews.core.spaces import HoloMap
  from holoviews.element import Labels
  from holoviews.plotting.bokeh.util import property_to_dict
  from ..utils import ParamLogStream
  from .test_plot import TestBokehPlot, bokeh_renderer
label_desc: Use image node_id 8 for calling the TestLabelsPlot obj's underlying member method code with example usage: obj.test_label_linear_color_op() without return types