NoseMultiVersion 0.1
A Nose plugin to run tests simultaneously in different versions of Python.
License: MIT License

========
Overview
========

NoseMultiVersion is a `Nose`_ plugin to run tests simultaneously in different versions of Python.  

When the plugin is activated, your test suite spawns off subprocesses to run the same tests in each Python interpreter then the results are printed in the main process.  It was designed for libraries or applications that want to support legacy versions of Python or for projects that need to work in virtual environments that are configured differently.  Because it uses sockets via execnet_ and parallel subprocesses, it only adds minimal overhead to your test time.

Installation
============

NoseMultiVersion, Nose_, and execnet_ must be installed in each version of Python you want to run your tests in.  Your test and application modules **do not** need to be installed in each Python version.

Here's how to install the NoseMultiVersion and its dependencies:

Install With Pip From Source
============================

Grab the `pip source`_ and do something like this::
    
    $ cd /pip/source
    $ sudo python2.4 ./scripts/pip install -e hg+http://bitbucket.org/kumar303/nose-multiversion/#egg=NoseMultiVersion
    $ sudo python2.5 ./scripts/pip install -e hg+http://bitbucket.org/kumar303/nose-multiversion/#egg=NoseMultiVersion
    $ sudo python2.6 ./scripts/pip install -e hg+http://bitbucket.org/kumar303/nose-multiversion/#egg=NoseMultiVersion

Install With Pip From PyPI
==========================

Just like above but do::
    
    $ cd /pip/source
    $ sudo python2.4 ./scripts/pip install NoseMultiVersion
    $ sudo python2.5 ./scripts/pip install NoseMultiVersion
    $ sudo python2.6 ./scripts/pip install NoseMultiVersion

Install With Setuptools
=======================
    
::
    
    $ sudo easy_install-2.4 http://bitbucket.org/kumar303/nose-multiversion/get/tip.zip
    $ sudo easy_install-2.5 http://bitbucket.org/kumar303/nose-multiversion/get/tip.zip
    $ sudo easy_install-2.6 http://bitbucket.org/kumar303/nose-multiversion/get/tip.zip

Run A Simple Test Suite In Multiple Versions of Python
======================================================

If you have an application without many dependencies you can probably just run the tests in multiple versions like this::
    
    $ cd /your/test/suite
    $ nosetests --in-python=2.4,2.5,2.6

Run A Complex Test Suite In A Virtualenv
========================================

It's most likely that your application has some dependencies that you are probably managing with a custom `virtualenv`_.  
The value passed to the ``--in-python=`` option can also be an absolute path to a Python interpreter so set up your virtualenv directories then run your tests like this::
    
    $ cd /your/test/suite
    $ nosetests --in-python=/path/to/a/virtualenv-for-2.5/bin/python --in-python=/path/to/a/virtualenv-for-2.6/bin/python

Declare Option Values in a Config Script
========================================

As with any Nose option, you can use a `config file`_ to set its value, like this::
    
    [nosetests]
    in-python= 
        /path/to/your-virtualenv1/bin/python
        /path/to/your-virtualenv2/bin/python
        /path/to/jython
        /path/to/your-custom-build/bin/python

Acknowledgements
================

This plugin was created by Kumar McMillan <kumar.mcmillan@gmail.com>.  Big thanks to Holger Krekel for extracting execnet_ into its own package.  This allowed Nose to steal a nice feature from `py.test`_ :)

Bugs, Patches
=============

Submit all bugs and patches to http://bitbucket.org/kumar303/nose-multiversion/ -- thanks!

Random Notes
============

- If another plugin tries to do a frame hack then it might break because tracebacks and frames are flattened then pickled so they can be sent from a worker to the main process.
- When `Nose supports Python 3.0`_ as well as execnet then adding 3.0 to your options should just magically work!
- There are probably some other nifty things to steal from py.test like decorators that raise Nose's SkipTest exception when you don't want to run a test in a specific version.

.. _Nose: http://somethingaboutorange.com/mrl/projects/nose
.. _Nose supports Python 3.0: http://bitbucket.org/jpellerin/nose3/
.. _execnet: http://codespeak.net/execnet/
.. _pip source: http://pypi.python.org/pypi/pip
.. _virtualenv: http://pypi.python.org/pypi/virtualenv
.. _config file: http://somethingaboutorange.com/mrl/projects/nose/0.11.1/usage.html
.. _py.test: http://codespeak.net/py/dist/test/