new_contents: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  
  """ Test case for Energy Profle Canvas.
  """
  
  import unittest
  
  from catplot.ep_components.ep_canvas import EPCanvas
  
  
  class EPCanvasTest(unittest.TestCase):
  
      def setUp(self):
          self.maxDiff = True
  
      def test_construction_and_query(self):
          """ Test we can construct ElementaryLine object correctly.
          """
          canvas = EPCanvas(margin_ratio=0.2)
  
          self.assertEqual(canvas.margin_ratio, 0.2)
          self.assertListEqual(canvas.lines, [])
          self.assertListEqual(canvas.shadow_lines, [])
          self.assertTrue(canvas.figure)
          self.assertTrue(canvas.axes)
  
          # Check invalid reaction equation.
          self.assertRaises(ValueError, EPCanvas, margin_ratio=-0.1)
  
  if "__main__" == __name__: 
      suite = unittest.TestLoader().loadTestsFromTestCase(EPCanvasTest)
      unittest.TextTestRunner(verbosity=2).run(suite) 
  
  
subject: Add test case for EPCanvas.