new_contents: import unittest
  
  import pandas.util.testing as pdt
  import recordlinkage
  import numpy as np
  import pandas as pd
  import os
  
  class TestIndexing(unittest.TestCase):
  
      def test_full_index_unique(self):
  
          df1 = pd.DataFrame({'name':['Bob', 'Anne', 'Micheal']}, index=['001', '002', '003'])
          df2 = pd.DataFrame({'name':['Bob', 'Anne', 'Micheal']}, index=['001', '002', '003'])
  
          index = recordlinkage.Pairs(df1, df2)
          pairs = index.full()
  
          index_exp = [('001', '001'), ('001', '002'), ('001', '003'), ('002', '001'), ('002', '002'), ('002', '003'), ('003', '001'), ('003', '002'), ('003', '003')]
  
          # Check if index is unique
          self.assertTrue(pairs.index.is_unique)
  
          # Check is number of pairs is correct
          self.assertEqual(len(pairs), len(df1)*len(df2))
  
      def test_block_index_unique(self):
  
          df1 = pd.DataFrame({'name':['Bob', 'Anne', 'Micheal']}, index=['001', '002', '003'])
          df2 = pd.DataFrame({'name':['Bob', 'Anne', 'Micheal']}, index=['001', '002', '003'])
  
          index = recordlinkage.Pairs(df1, df2)
          pairs = index.block('name')
  
          index_exp = [('001', '001'), ('002', '002'),('003', '003')]
  
          # Check if index is unique
          self.assertTrue(pairs.index.is_unique)
  
          # Check is number of pairs is correct
          self.assertEqual(len(pairs), 3)
  
      def test_sortedneighbourhood_index_unique(self):
  
          df1 = pd.DataFrame({'name':['Bob', 'Anne', 'Micheal']}, index=['001', '002', '003'])
          df2 = pd.DataFrame({'name':['Bob', 'Anne', 'Micheal']}, index=['001', '002', '003'])
  
          index = recordlinkage.Pairs(df1, df2)
          pairs = index.sortedneighbourhood('name')
  
          index_exp = [('001', '001'), ('002', '002'),('003', '003')]
  
          # Check if index is unique
          self.assertTrue(pairs.index.is_unique)
  
  
  
  
  if __name__ == '__main__':
      unittest.main()
subject: Add indexing tests