Integration testing in python, suggested tools and practices?

I've some hard time understanding Integration testing in general, I want to do some integration testing in python expecially for network programming in twisted (but I want to know something more in general).

There are any good resource I must read, and tools (python tools if possible), practices that introduces me in integration testing?

Which tool is used for integration testing?

Citrus. It is the most commonly used integration testing tool, which is a test framework and written in the Java programming language.

What is integration testing in Python?

Integration testing is the testing of multiple components of the application to check that they work together. Integration testing might require acting like a consumer or user of the application by: Calling an HTTP REST API. Calling a Python API. Calling a web service.

The recent Pycon had many talks on testing. All of the videos are available on Vimeo and the slides can be downloaded.: http://us.pycon.org/2010/conference/talks/?filter=testing

Specifically, I recommend the talk by Ned Batchelder. The other ones are probably good too. (altho' I haven't seen them)