Writing and testing pysource2

Author: Tibs
Contact: tibs@tibsnjoan.co.uk
Revision: 1721
Date: 2003-10-21
Copyright: This document has been placed in the public domain.

pysource2 is my attempt to rewrite the original pysource. pysource itself was a proof-of-concept module to find docstrings withing Python source files and present them as (by default) HTML documentation, as described by the Docutils project. Since it was written before the Docutils codebase became stabilised around its current Reader/Writer patterns, it doesn't really mesh well with the current approaches. Also, lots of the code is fairly grotty anyway, and could do with a rewrite on principle - not least because it is not well tested.

So, pysource2 is both that rewrite, and also an attempt on my part to learn how to do test driven development.

Setting the path

I want to take my docutils stuff directly from the source directories, so that I work with the latest CVS code, and don't have to keep installing things. Thus I need to set the Python path to point to the source directories:

export PYTHONPATH=${PYTHONPATH}:${HOME}/docutils

Since I'm using Python 2.2.3, I also need the modules in the "extras" directory:

export PYTHONPATH=${PYTHONPATH}:${HOME}/docutils/extras

If I want access to the testing stuff, I also need the "test" directory:

export PYTHONPATH=${PYTHONPATH}:${HOME}/docutils/test

NB: Relies upon the code in docutils/docutils/readers/python/moduleparser.py


The "obvious" place to start is with packages - the previous pysource never did quite get them right (for a start, it wouldn't cope with sub-packages). Also, having a utility to report on packages, then on modules, and gradually on to finer levels of detail, seems like giving something useful as soon as possible.

It looked over-complex to adopt the docutils test framework itself, initially, especially since I am new both to unit testing and to test driven development. So I am being less ambitious, and working with "pure" unit tests - I reckon I'll learn more that way.

So, the first pass gives me package.py and test_package.py.

My first impressions of (such a little bit of) development is that TDD does indeed give one the feeling of reassurance I'd expected from my half-TDD efforts in Java at LSL.

Initially, I was looking to detect a request for a package that didn't exist, or wasn't a directory file, explicitly, with dedicated exceptions. This felt rather over-complex, and indeed refactoring those tests out and just catching a (non-explicit) OSError in the tests works well enough - in reality, a user is not going to ask to parse a package that is not already known to be an existant directory (heck, the "user" is probably a program that's just figured out if the thing whose documentation is wanted is a file or a directory), and if they do then OSError makes sense since it is what one would normally get.



  • Add a method to Module to indicate if it has an Attribute called __docformat__, and if so, what its value is.
  • That requires understanding how the testing for the moduleparser is organised and works, so I can add an appropriate test.
  • At which stage, should I incorporate Package (and NotPython) therein?
  • Write a simple transform (first learn how!) to parse any Docstring contents in a module with __docformat__ equal to one of the reStructuredText indicators.
  • Write another transform to turn the Pythonic doctree into a standard one.
  • At which point, we'll have something useful, albeit not very powerful, so provide an appropriate command line interface for (at least) HTML output.
  • Work out how to do attribute references, etc., in this context (I have no idea if the mechanisms from the original pysource will be any use).