new_contents: 
  import os
  import mock
  
  from django.core.management import call_command
  from django.db.utils import DatabaseError
  from django.test import TestCase
  
  
  devnull = open(os.devnull, 'w')
  
  
  @mock.patch("sys.stdout", devnull)  # Get rid of output this command prints to user
  class SanityCheckTest(TestCase):
  
      def test_sanity_check_command_positive(self):
          call_command("sanity_check")
  
      def test_sanity_check_negative(self):
          # We want to check if this command fails if there is any connection error
          # to the database, so we are patching cursor() call
          with mock.patch("django.db.connection.cursor", side_effect=DatabaseError()):
              with self.assertRaises(Exception):
                  call_command("sanity_check")
  
subject: Add tests to sanity check command