code: def test_curve_interpolation(self):
      curve = Curve([1, 2, 3]).opts(interpolation="steps-mid")
      state = self._get_plot_state(curve)
      self.assertEqual(
          state["data"][0]["x"],
          np.array([0.0, 0.5, 0.5, 1.5, 1.5, 2.0]),
      )
      self.assertEqual(
          state["data"][0]["y"], np.array([1, 1, 2, 2, 3, 3])
      )
  
imports: import numpy
  from holoviews.element import Curve, Tiles
  from .test_plot import TestPlotlyPlot
label_desc: Use image node_id 3 for calling the TestCurvePlot obj's underlying member method code with example usage: obj.test_curve_interpolation() without return types