text: import unittest
  
  class Empty:
      def __repr__(self):
          return '<Empty>'
  
  class Cmp:
      def __init__(self,arg):
          self.arg = arg
  
      def __repr__(self):
          return '<Cmp %s>' % self.arg
  
      def __eq__(self, other):
          return self.arg == other
  
  class Anything:
      def __eq__(self, other):
          return True
  
      def __ne__(self, other):
          return False
  
  class ComparisonTest(unittest.TestCase):
      set1 = [2, 2.0, 2, 2+0j, Cmp(2.0)]
      set2 = [[1], (3,), None, Empty()]
      candidates = set1 + set2
  
      def test_comparisons(self):
          for a in self.candidates:
              for b in self.candidates:
                  if ((a in self.set1) and (b in self.set1)) or a is b:
                      self.assertEqual(a, b)
                  else:
                      self.assertNotEqual(a, b)
  
      def test_id_comparisons(self):
          # Ensure default comparison compares id() of args
          L = []
          for i in range(10):
              L.insert(len(L)//2, Empty())
          for a in L:
              for b in L:
                  self.assertEqual(a == b, id(a) == id(b),
                                   'a=%r, b=%r' % (a, b))
  
      def test_ne_defaults_to_not_eq(self):
          a = Cmp(1)
          b = Cmp(1)
          c = Cmp(2)
          self.assertIs(a == b, True)
          # self.assertIs(a != b, False)
          self.assertIs(a != c, True)
  
      # def test_ne_high_priority(self):
      #     """object.__ne__() should allow reflected __ne__() to be tried"""
      #     calls = []
      #     class Left:
      #         # Inherits object.__ne__()
      #         def __eq__(*args):
      #             calls.append('Left.__eq__')
      #             return NotImplemented
      #     class Right:
      #         def __eq__(*args):
      #             calls.append('Right.__eq__')
      #             return NotImplemented
      #         def __ne__(*args):
      #             calls.append('Right.__ne__')
      #             return NotImplemented
      #     Left() != Right()
      #     self.assertSequenceEqual(calls, ['Left.__eq__', 'Right.__ne__'])
  
      # def test_ne_low_priority(self):
      #     """object.__ne__() should not invoke reflected __eq__()"""
      #     calls = []
      #     class Base:
      #         # Inherits object.__ne__()
      #         def __eq__(*args):
      #             calls.append('Base.__eq__')
      #             return NotImplemented
      #     class Derived(Base):  # Subclassing forces higher priority
      #         def __eq__(*args):
      #             calls.append('Derived.__eq__')
      #             return NotImplemented
      #         def __ne__(*args):
      #             calls.append('Derived.__ne__')
      #             return NotImplemented
      #     Base() != Derived()
      #     self.assertSequenceEqual(calls, ['Derived.__ne__', 'Base.__eq__'])
  
      def test_other_delegation(self):
          """No default delegation between operations except __ne__()"""
          ops = (
              ('__eq__', lambda a, b: a == b),
              ('__lt__', lambda a, b: a < b),
              ('__le__', lambda a, b: a <= b),
              ('__gt__', lambda a, b: a > b),
              ('__ge__', lambda a, b: a >= b),
          )
  
      def test_issue_1393(self):
          x = lambda: None
          self.assertEqual(x, Anything())
          self.assertEqual(Anything(), x)
          y = object()
          self.assertEqual(y, Anything())
          self.assertEqual(Anything(), y)
  
  
  if __name__ == '__main__':
      unittest.main()
  