text: from __future__ import division, print_function, absolute_import
  
  from numpy.testing import dec, assert_, assert_array_equal
  
  try:
      import matplotlib
      matplotlib.rcParams['backend'] = 'Agg'
      import matplotlib.pyplot as plt
      from matplotlib.collections import LineCollection
      has_matplotlib = True
  except:
      has_matplotlib = False
  
  from scipy.spatial import \
       delaunay_plot_2d, voronoi_plot_2d, convex_hull_plot_2d, \
       Delaunay, Voronoi, ConvexHull
  
  
  class TestPlotting:
      points = [(0,0), (0,1), (1,0), (1,1)]
  
      @dec.skipif(not has_matplotlib, "Matplotlib not available")
      def test_delaunay(self):
          # Smoke test
          fig = plt.figure()
          obj = Delaunay(self.points)
          s_before = obj.simplices.copy()
          r = delaunay_plot_2d(obj, ax=fig.gca())
          assert_array_equal(obj.simplices, s_before)  # shouldn't modify
          assert_(r is fig)
          delaunay_plot_2d(obj, ax=fig.gca())
  
      @dec.skipif(not has_matplotlib, "Matplotlib not available")
      def test_voronoi(self):
          # Smoke test
          fig = plt.figure()
          obj = Voronoi(self.points)
          r = voronoi_plot_2d(obj, ax=fig.gca())
          assert_(r is fig)
          voronoi_plot_2d(obj)
          voronoi_plot_2d(obj, show_vertices=False)
  
      @dec.skipif(not has_matplotlib, "Matplotlib not available")
      def test_convex_hull(self):
          # Smoke test
          fig = plt.figure()
          tri = ConvexHull(self.points)
          r = convex_hull_plot_2d(tri, ax=fig.gca())
          assert_(r is fig)
          convex_hull_plot_2d(tri)
  