new_contents: import unittest
  import numpy as np
  import protosel
  
  
  def load_orings():
  
      # Load Challenger USA Space Shuttle O-Ring data set
      # Attributes information:
      # 1st attribute: Number of o-rings at risk on a given flight
      # 2nd attribute: Number experiencing thermal distress
      # 3rd attribute: Launch temperature (degrees F)
      # 4th attribute: Leak-check pressure (psi)
      # 5th attribute: Temporal order of flight
      dataset = np.array([
          [6, 0, 66,  50,  1],
          [6, 1, 70,  50,  2],
          [6, 0, 69,  50,  3],
          [6, 0, 68,  50,  4],
          [6, 0, 67,  50,  5],
          [6, 0, 72,  50,  6],
          [6, 0, 73, 100,  7],
          [6, 0, 70, 100,  8],
          [6, 1, 57, 200,  9],
          [6, 1, 63, 200, 10],
          [6, 1, 70, 200, 11],
          [6, 0, 78, 200, 12],
          [6, 0, 67, 200, 13],
          [6, 2, 53, 200, 14],
          [6, 0, 67, 200, 15],
          [6, 0, 75, 200, 16],
          [6, 0, 70, 200, 17],
          [6, 0, 81, 200, 18],
          [6, 0, 76, 200, 19],
          [6, 0, 79, 200, 20],
          [6, 0, 75, 200, 21],
          [6, 0, 76, 200, 22],
          [6, 1, 58, 200, 23]
      ])
  
      data = dataset[:, np.arange(5) != 1]
      target = dataset[:, 1]
      return data, target
  
  
  class TestISA(unittest.TestCase):
      """Test an instance selection algorithm."""
  
      @classmethod
      def setUpClass(self):
          # Load test dataset
          self.data, self.target = load_orings()
  
      def test_enn(self):
          obtained_results = protosel.enn(self.data, self.target).tolist()
          expected_results = [True, False, True, True, True, True, True, True,
                              True, True, False, True, True, False, True, True,
                              True, True, True, True, True, True, False]
          self.assertEqual(obtained_results, expected_results)
  
  
  if __name__ == '__main__':
      unittest.main()
  
subject: Add test coverage for ENN