def test_coordinates(self):
     ellipse = Ellipse(center=('1cm','1cm'), r=('2mm', '1mm'))
     self.assertEqual(ellipse.tostring(), '<ellipse cx="1cm" cy="1cm" rx="2mm" ry="1mm" />')
 def test_numbers(self):
     ellipse = Ellipse(center=(0,0), r=(2,1))
     self.assertEqual(ellipse.tostring(), '<ellipse cx="0" cy="0" rx="2" ry="1" />')