That is a really cool and very practical use of Test:MockObject. However I don't think the analogy holds because I want the whole environment to be real and not fake: real environment variables, real input and a real CGI or equivalent object. Have a look at the CGI test script I cited. That is really what I want to do - but it depends on an input file that is not in a strictly human readable format. So essentially what I want to do is make that input file maintainable by humans.