What is the typical Pythonic view on re-using python modules outside of their initial intent?

Question

Short Question
Does it fly in the face of the Pythonic view to reuse / repurpose python modules for projects out side of their intent?

Background
Over the past several months I have been working on a project that uses the Python unittest module to run manual system tests. Please see questions 1 2 and 3 for greater detail on my project and some of the hurdles I have had to overcome.

I would like to know, in general, if it acceptable to reuse modules for other purposes? Most of the comments I have received have been along the lines of "this is not a unittest", or "you should write your own testrunner". My push back on that, is if a module does 90% of what you need it to do with litte to no modification and contains additional (knowingly unneeded) functionality why on earth would you write your own module?

Answer 1

Using the code for more than what the original authors intended is usually a good sign, in that the code provides useful tools. As far as re-purposing modules "outside of their intent" is concerned, well... this is obviously subjective and depends to what extent.

Using raw I/O functions in imaplib to implement some unrelated socket-based communication protocol could be considered bad style (to say the least). However, using the same imaplib library to implement some private variant of the IMAP protocol (unlikely to be the intended use) would be IMHO less of a problem.

It's totally understandable that you would find some convenient classes and methods in the unittest module to implement other types of tests. However, the problem is often one of code readability. To most Python developers, seeing the unittest module closely to the idiomatic recommended usage probably conveys the meaning of "this piece of code is a unit test". In terms of "self-documenting code", this is a total failure in the sens that it is misleading for other developers.

Ideally, this would be a non-question. The solution would be to refactor the unittest module so that code not specific to unit tests is moved to a test module or testbase module or some such thing. However, you might find a lot of resistance in such an effort, for political and practical reasons. It is, after all, a standard library module and can't be modified as easily as your own project.

Does it fly in the face of the Pythonic view to reuse / repurpose python modules for projects out side of their intent?

In general, I don't think this is "anti-Pythonic", although I think the fact that these comments have occured several times should mean something.

Maybe you can write some sort of systemtest module that imports the re-usable stuff from the unittest module. It's a temporary solution that gives both code clarity and allows you to re-use the code directly. Then, you can write a long comment in the systemtest module about how all the workarounds are actually better than writing your own test runner.