old_contents: import unittest
  
  import inidiff
  
  INI_1 = '''[test]
  number=10
  '''
  
  INI_2 = '''[test]
  number=20
  '''
  
  
  class TestDiff(unittest.TestCase):
      """Test diffs diff things."""
  
      def test_no_differences(self):
          self.assertEqual([], inidiff.diff(INI_1, INI_1))
  
      def test_some_differences(self):
          self.assertTrue(len(inidiff.diff(INI_1, INI_2)) > 0)
  
new_contents: import unittest
  
  import inidiff
  
  INI_1 = '''[test]
  number=10
  '''
  
  INI_2 = '''[test]
  number=20
  '''
  
  
  class TestDiff(unittest.TestCase):
      """Test diffs diff things."""
  
      def test_no_differences(self):
          self.assertEqual([], inidiff.diff(INI_1, INI_1))
  
      def test_some_differences(self):
          self.assertTrue(len(inidiff.diff(INI_1, INI_2)) > 0)
  
      def test_number_is_different(self):
          diffs = inidiff.diff(INI_1, INI_2)
          first, second = diffs[0]
          self.assertEqual('number', first[1])
  
subject: Check number is the field that is different