old_contents: import unittest
  import env
  
  from src.ConnectionList import ConnectionList 
  from src.CityList import CityList 
  
  #Check one city length as sanity check
  class TestNumConnectionsMontreal(unittest.TestCase):
      def runTest(self):
          self.assertEqual(len(ConnectionList["Montreal"]), 3)
  
  #Check each key of connection is a valid city entry, catch typos
  class TestAllKeysAreCities(unittest.TestCase):
      def runTest(self):
          for key in ConnectionList:
              self.assertTrue(key in CityList)
  
  #Check each item in array value of connection is a valid city entry, catch typos
  class TestAllValuesAreCities(unittest.TestCase):
      def runTest(self):
          for key in ConnectionList:
              for value in ConnectionList[key]:
                  self.assertTrue(value in CityList, "City " + value + " not in City List")
  
  #Every city must be connected at least once
  class TestAllCitiesAreInConnection(unittest.TestCase):
      def runTest(self):
          for key in CityList:
              self.assertTrue(key in ConnectionList)
  
  #For all connections if from city a to city b connects,
  #Then from city b to city a should also connect
  class TestAllConnectionsBidirectional(unittest.TestCase):
      def runTest(self):
          #TODO this test.
          self.assertTrue(False)
  
new_contents: import unittest
  import env
  
  from src.ConnectionList import ConnectionList 
  from src.CityList import CityList 
  
  #Check one city length as sanity check
  class TestNumConnectionsMontreal(unittest.TestCase):
      def runTest(self):
          self.assertEqual(len(ConnectionList["Montreal"]), 3)
  
  #Check each key of connection is a valid city entry, catch typos
  class TestAllKeysAreCities(unittest.TestCase):
      def runTest(self):
          for key in ConnectionList:
              self.assertTrue(key in CityList)
  
  #Check each item in array value of connection is a valid city entry, catch typos
  class TestAllValuesAreCities(unittest.TestCase):
      def runTest(self):
          for key in ConnectionList:
              for value in ConnectionList[key]:
                  self.assertTrue(value in CityList, "City " + value + " not in City List")
  
  #Every city must be connected at least once
  class TestAllCitiesAreInConnection(unittest.TestCase):
      def runTest(self):
          for key in CityList:
              self.assertTrue(key in ConnectionList)
  
  
  #No city should connect to itself
  class TestNoCityConnectsToSelf(unittest.TestCase):
      def runTest(self):
          for key in CityList:
              for value in ConnectionList[key]:
                  self.assertNotEqual(key, value)
  
  #For all connections if from city a to city b connects,
  #Then from city b to city a should also connect
  class TestAllConnectionsBidirectional(unittest.TestCase):
      def runTest(self):
          #TODO this test.
          self.assertTrue(False)
  
subject: Add unit test