code: def test_spikes_padding_datetime_square_heights(self):
      spikes = Spikes(
          [(np.datetime64("2016-04-0%d" % i), i) for i in range(1, 4)],
          vdims=["Height"],
      ).opts(padding=0.1)
      plot = mpl_renderer.get_plot(spikes)
      x_range, y_range = (
          plot.handles["axis"].get_xlim(),
          plot.handles["axis"].get_ylim(),
      )
      self.assertEqual(x_range[0], 16891.8)
      self.assertEqual(x_range[1], 16894.2)
      self.assertEqual(y_range[0], 0)
      self.assertEqual(y_range[1], 3.2)
  
imports: import numpy
  import pytest
  from holoviews.core.options import AbbreviatedException
  from holoviews.core.overlay import NdOverlay
  from holoviews.core.spaces import HoloMap
  from holoviews.element import Spikes
  from ..utils import ParamLogStream
  from .test_plot import TestMPLPlot, mpl_renderer
label_desc: Use image node_id 9 for calling the TestSpikesPlot obj's underlying member method code with example usage: obj.test_spikes_padding_datetime_square_heights() without return types