code: def test_hex_tiles_opts(self):
      from holoviews.plotting.util import process_cmap
  
      tiles = HexTiles([(0, 0), (0.5, 0.5), (-0.5, -0.5), (-0.4, -0.4)])
      plot = mpl_renderer.get_plot(tiles)
      args, style, _ = plot.get_data(tiles, {}, {})
      self.assertEqual(args[0], tiles["x"])
      self.assertEqual(args[1], tiles["y"])
      self.assertEqual(args[2], np.ones(4))
      cmap = style.pop("cmap")
      self.assertEqual(
          style,
          {
              "reduce_C_function": np.sum,
              "vmin": None,
              "vmax": None,
              "xscale": "linear",
              "yscale": "linear",
              "gridsize": 50,
              "mincnt": None,
          },
      )
      self.assertEqual(cmap.colors, process_cmap("viridis"))
  
imports: import numpy
  from holoviews.element import HexTiles
  from .test_plot import TestMPLPlot, mpl_renderer
label_desc: Use image node_id 2 for calling the TestHexTilesPlot obj's underlying member method code with example usage: obj.test_hex_tiles_opts() without return types