Learning by examples
------------------------

XXX

adding custom options
+++++++++++++++++++++++

py.test supports adding of standard optparse_ Options. 
A plugin may implement the ``addoption`` hook for registering 
custom options:: 

    class ConftestPlugin:
        def pytest_addoption(self, parser):
            parser.addoption("-M", "--myopt", action="store", 
                help="specify string to set myopt")

        def pytest_configure(self, config):
            if config.option.myopt:
                # do action based on option value

.. _optparse: http://docs.python.org/library/optparse.html

Setting default values for test options
-----------------------------------------

You can see all available command line options by running::

    py.test -h 

py.test will lookup values of options in this order:

* option value supplied at command line 
* content of environment variable ``PYTEST_OPTION_NAME=...``
* ``name = ...`` setting in the nearest ``conftest.py`` file.

The name of an option usually is the one you find 
in the longform of the option, i.e. the name 
behind the ``--`` double-dash. 

IOW, you can set default values for options per project, per
home-directoray, per shell session or per test-run. 



Plugin methods 
----------------------------------

A Plugin class may implement the following attributes and methods: 

XXX

_`pytest event`: 

Pytest Events 
-------------------

XXX