new_contents: import unittest
  
  from dimod.views import VariableIndexView
  
  
  class TestVariableView(unittest.TestCase):
      def test_duplicates(self):
          # should have no duplicates
          variables = VariableIndexView(['a', 'b', 'c', 'b'])
          self.assertEqual(list(variables), ['a', 'b', 'c'])
  
      def test_iterable(self):
          variables = VariableIndexView('abcdef')
          self.assertEqual(list(variables), list('abcdef'))
  
      def test_index(self):
          variables = VariableIndexView(range(5))
          self.assertEqual(variables.index(4), 4)
  
      def test_count(self):
          variables = VariableIndexView([1, 1, 1, 4, 5])
          self.assertEqual(list(variables), [1, 4, 5])
          for v in range(10):
              if v in variables:
                  self.assertEqual(variables.count(v), 1)
              else:
                  self.assertEqual(variables.count(v), 0)
  
      def test_len(self):
          variables = VariableIndexView(range(5))
          self.assertEqual(len(variables), 5)
          variables = VariableIndexView('aaaaa')
          self.assertEqual(len(variables), 1)
  
subject: Add unittests for VariableIndexView