old_contents: from robber import expect
  from robber.matchers.equal import Equal, NotEqual
  
  
  class TestEqual:
      def test_matches(self):
          expect(Equal(1, 1).matches()).to.eq(True)
          expect(Equal(1, 2).matches()).to.eq(False)
  
      def test_failure_message(self):
          equal = Equal('actual', 'expected')
          message = equal.failure_message()
          expect(message) == 'Expected "actual" to equal "expected"'
  
      def test_register(self):
          expect(expect.matcher('eq')) == Equal
          expect(expect.matcher('__eq__')) == Equal
  
  
  class TestNotEqual:
      def test_matches(self):
          expect(NotEqual(1, 2).matches()).to.eq(True)
          expect(NotEqual(1, 1).matches()).to.eq(False)
  
      def test_failure_message(self):
          equal = NotEqual('actual', 'expected')
          message = equal.failure_message()
          expect(message) == 'Expected "actual" not to equal "expected"'
  
      def test_register(self):
          expect(expect.matcher('not_eq')) == NotEqual
          expect(expect.matcher('ne')) == NotEqual
          expect(expect.matcher('__ne__')) == NotEqual
  
new_contents: from robber import expect
  from robber.matchers.equal import Equal, NotEqual
  
  
  class TestEqual:
      def test_matches(self):
          expect(Equal(1, 1).matches()).to.eq(True)
          expect(Equal(1, 2).matches()).to.eq(False)
  
      def test_failure_message(self):
          equal = Equal('actual', 'expected')
          message = equal.failure_message()
          expect(message) == 'Expected "actual" to equal "expected"'
  
      def test_failure_message_with_not_to(self):
          equal = Equal('actual', 'actual', is_negated=True)
          message = equal.failure_message()
          expect(message) == 'Expected "actual" not to equal "actual"'
  
      def test_register(self):
          expect(expect.matcher('eq')) == Equal
          expect(expect.matcher('__eq__')) == Equal
  
  
  class TestNotEqual:
      def test_matches(self):
          expect(NotEqual(1, 2).matches()).to.eq(True)
          expect(NotEqual(1, 1).matches()).to.eq(False)
  
      def test_failure_message(self):
          equal = NotEqual('actual', 'expected')
          message = equal.failure_message()
          expect(message) == 'Expected "actual" not to equal "expected"'
  
      def test_register(self):
          expect(expect.matcher('not_eq')) == NotEqual
          expect(expect.matcher('ne')) == NotEqual
          expect(expect.matcher('__ne__')) == NotEqual
  
subject: Add failure message test for not_to.be.eq