example.py

#!/usr/bin/env python

import libcloud.providers
import libcloud.types

from secret import USERNAME, PASSWORD

class Example(object):

    def __init__(self):
        driver = libcloud.providers.get_driver(
                libcloud.types.Provider.RACKSPACE
                )   

        self.connection = driver(USERNAME, PASSWORD)

    def node_names(self):
        return [node.name for node in self.connection.list_nodes()]

if __name__ == "__main__":
    example = Example()

    print example.node_names()

test_example.py

#!/usr/bin/env python
                
import unittest 
                
import mox
import libcloud.providers
from libcloud.drivers.rackspace import RackspaceNodeDriver
        
from example import Example

class TestExample(unittest.TestCase):
    
    def setUp(self):
        self.mox = mox.Mox()

    def tearDown(self):
        self.mox.UnsetStubs()
               
    def test_that_node_names_calls_list_nodes(self):
        mocked_driver = self.mox.CreateMock(RackspaceNodeDriver)

        mocked_driver.list_nodes().AndReturn([            
            type("Node", (), {"name": "node1"}),
            type("Node", (), {"name": "node2"})
                    ])
                                     
        self.mox.StubOutWithMock(libcloud, "providers",
                use_mock_anything=True)
        libcloud.providers.get_driver(mox.IgnoreArg()).AndReturn(
                lambda *args, **kwargs: mocked_driver)
                       
        self.mox.ReplayAll() 
        
        example = Example()                         
        node_names = example.node_names()
        
        self.assertEqual(set(node_names), set(["node1", "node2"]))
        
        self.mox.VerifyAll() 
            
if __name__ == "__main__":
    unittest.main()