code: def test_image_stack(self):
      try:
          import datashader  # noqa: F401
      except ImportError:
          raise SkipTest("Test requires datashader")
      x = np.arange(0, 3)
      y = np.arange(5, 8)
      a = np.array([[np.nan, np.nan, 1], [np.nan] * 3, [np.nan] * 3])
      b = np.array([[np.nan] * 3, [1, 1, np.nan], [np.nan] * 3])
      c = np.array([[np.nan] * 3, [np.nan] * 3, [1, 1, 1]])
  
      img_stack = ImageStack(
          (x, y, a, b, c), kdims=["x", "y"], vdims=["a", "b", "c"]
      )
      plot = mpl_renderer.get_plot(img_stack)
      artist = plot.handles["artist"]
      array = artist.get_array().data
      assert array.shape == (3, 3, 4)
      assert artist.get_extent() == [-0.5, 2.5, 4.5, 7.5]
      assert isinstance(plot, RGBPlot)
  
file_path: holoviews/holoviews/tests/plotting/matplotlib/test_rasterplot.py
imports: from unittest import SkipTest
  import numpy
  from matplotlib.colors import ListedColormap
  from holoviews.element import Image, ImageStack, Raster
  from holoviews.plotting.mpl.raster import RGBPlot
  from .test_plot import TestMPLPlot, mpl_renderer
label_desc: Use image node_id 10 for calling the TestRasterPlot obj's underlying member method code with example usage: obj.test_image_stack() without return types