docstr: Test initialization of ColumnDataSources.
  
          
docstr_tok: ["Test","initialization","of","ColumnDataSources","."]
code: def test_plot_data_source(self):
      """Test initialization of ColumnDataSources."""
  
      source_ann = self.plot.handles["annular_wedge_1_source"].data
  
      self.assertEqual(list(source_ann["x"]), list(self.x))
      self.assertEqual(list(source_ann["y"]), list(self.y))
      self.assertEqual(list(source_ann["z"]), self.z)
  
imports: from itertools import product
  import numpy
  from bokeh.models import ColorBar
  from holoviews.core.spaces import HoloMap
  from holoviews.element.raster import HeatMap
  from holoviews.plotting.bokeh import RadialHeatMapPlot
  from .test_plot import TestBokehPlot, bokeh_renderer
label_desc: Use image node_id 15 for calling the BokehRadialHeatMapPlotTests obj's underlying member method code with example usage: obj.test_plot_data_source() without return types