new_contents: import os
  import unittest
  
  import clib
  from clib.utils import Box
  
  
  class BboxTest(unittest.TestCase):
      def setUp(self):
          self.bbox = Box(50, 50, 40, 60)
  
      def test_vi_bbox(self):
          self.assertEqual(self.bbox.int_left_top(), (30, 20))
          self.assertEqual(self.bbox.int_right_bottom(), (70, 80))
  
  if __name__ == '__main__':
      unittest.main()
  
subject: Test code of Box.