new_contents: #!/usr/bin/env python
  
  """
  Regression test for pty leak in Node()
  """
  
  import unittest
  
  from mininet.net import Mininet
  from mininet.clean import cleanup
  from mininet.topo import SingleSwitchTopo
  
  class TestPtyLeak( unittest.TestCase ):
      "Verify that there is no pty leakage"
  
      @staticmethod
      def testPtyLeak():
          "Test for pty leakage"
          net = Mininet( SingleSwitchTopo() )
          net.start()
          host = net[ 'h1' ]
          for _ in range( 0, 10 ):
              oldptys = host.slave, host.master
              net.delHost( host )
              host = net.addHost( 'h1' )
              assert ( host.slave, host.master ) == oldptys
          net.stop()
  
  if __name__ == '__main__':
      unittest.main()
      cleanup()
  
subject: Test for Node()/Host() pty leakage