Unit tests and mock objects for telnet

I would like to write unit tests for my A class. A class is utilizes telnet class (standard) and I substitute the telnet module with MockTelnet. Class A may work with various telnet hosts and outputs of these hosts are different, that's why I use different ('command':'output') dictionaries to emulate different hosts.

QUESTIONS:

• Is my approach to mocking telnet for different hosts viable or there is a better approach?

• How is it possible to substitute dictionaries (let's say from dictFirst to dictSecond) within a single unit test testTelnetConnection?

  import unittest
  from mock import patch
  import telnetlib
  
  
  class A:
  
      def __init__(self, ip):
          telnet = telnetlib.Telnet(ip)
          telnet.write('admin\n')
          out1 = telnet.read_until('something')
          telnet.write('password\n')
          out2 = telnet.read_until('something')
          #Do something with out1 and out2
  
      def SomeMethod(self):
          pass
  
  class MockTelnet:
  
      command = None
      dictTelnet = None
  
      def __init__(self, ip, dictTelnet):
          print 'MockTelnet.__init__: ' + ip
          self.dictTelnet = dictTelnet
  
      def write(self, text):
          print 'MockTelnet.write: ' + text
          self.command = text
  
      def read_until(self, until): 
          return self.dictTelnet[self.command]
  
  
  class ATests(unittest.TestCase):
  
      dictFirst = {'admin\n':'Asomething', 'password\n':'Bsomething'}
      dictSecond = {'admin\n':'Csomething', 'password\n':'Dsomething'}
  
      @patch('telnetlib.Telnet', return_value = MockTelnet('192.168.0.1',dictFirst))    
      def testTelnetConnection(self,telnetlib_init):
          telnet = A('192.168.0.1')
          #Need to select dictSecond for MockTelnet here
          telnet = A('192.168.0.2')
  
  if __name__ == '__main__':
      unittest.main()