[Tutor] unittest: looking for examples

[Christian Meesters]

Hi

Does anybody know examples using the unittest module for the following 
cases (or some parts of it)?

- unittests for methods of classes getting all data from a file as a 
classmethod
- unittests for reading and saving files in a specific way (= sanity 
tests for file handling)

Point is that I want to test such methods directly, but also that I 
cannot set up unittest in my case without getting some data from a file 
(otherwise my testing module would get way too big). I've found lots of 
material on unittesting in various books and on the net, but none of 
the sources I've seen covers those two questions.

I'd appreciate just any pointer on such material.

TIA
Christian