nose-testconfig 0.1

testconfig
==========

.. contents::

About
------------------

Written by Jesse Noller
Licensed under the Apache Software License, 2.0

You can install it with ``easy_install virtualenv``

What It Does
------------

nose-testconfig is a plugin to the nose test framework which provides a
faculty for passing test-specific (or test-run specific) configuration data
to the tests being executed.

Currently configuration files in the following formats are supported:
* YAML (via `Pyyaml <http://pypi.python.org/pypi/PyYAML/>`)
* INI (via `ConfigParser <http://docs.python.org/lib/module-ConfigParser.html>`)
* Pure Python (via Exec)

The plugin is ``meant`` to be flexible, ergo the support of exec'ing arbitrary
python files as configuration files with no checks. The default format is
assumed to be ConfigParser ini-style format.

The plugin provides a method of overriding certain parameters from the command
line (assuming that the main "config" object is a dict) and can easily have
additional parsers added to it.

``Warning``: By default, when parsing ini-style files, the value in the
key = value pair is loaded via an eval() statement - this is designed so that
you can put python lists or dictionaries into the values and have them parsed
into actual data structures. This may not be desirable for some as it is both
dangerous, and forces values to be valid python syntax.

Test Usage
----------

For now (until something better comes along) tests can import the "config"
singleton from testconfig:

from testconfig import config

By default, YAML files parse into a nested dictionary, and ConfigParser ini
files are also collapsed into a nested dictionary for foo[bar][baz] style
access. Tests can obviously access configuration data by referencing the
relevant dictionary keys:

from testconfig import config
def test_foo():
target_server_ip = config[servers][webapp_ip]

``Warning``: Given this is just a dictionary singleton, tests can easily write
into the configuration. This means that your tests can write into the config
space and possibly alter it. This also means that threaded access into the
configuration can be interesting.

When using pure python configuration - obviously the "sky is the the limit" -
given that the configuration is loaded via an exec, you could potentially
modify nose, the plugin, etc. However, if you do not export a config{} dict
as part of your python code, you obviously won't be able to import the
config object from testconfig.

When using YAML-style configuration, you get a lot of the power of pure python
without the danger of unprotected exec() - you can obviously use the pyaml
python-specific objects and all of the other YAML creamy goodness.

Defining a configuration file
-----------------------------

Simple ConfigParser style:

[myapp_servers]
main_server = 10.1.1.1
secondary_server = 10.1.1.2

So your tests access the config options like this:

from testconfig import config
def test_foo():
main_server = config['myapp_servers']['main_server']

If you wanted, you could set main_server to be a list named "main_servers"
like this: main_servers = ['10.1.1.1', '10.2.1.1'] - this would in turn be
eval'ed into a proper python list.

YAML style configuration:
myapp:
servers:
main_server: 10.1.1.1
secondary_server: 10.1.1.2

And your tests can access it thus:

from testconfig import config
def test_foo():
main_server = config['myapp']['servers']['main_server']

Python configuration file:

import socket

global config
config = {}
possible_main_servers = ['10.1.1.1', '10.1.1.2']

for srv in possible_main_servers:
try:
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((srv, 80))
except:
continue
s.close()
config['main_server'] = srv
break

And lo, the config is thus:

from testconfig import config
def test_foo():
main_server = config['main_server']


Command line options
--------------------

After it is installed, the plugin adds the following command line flags to
nosetests:

--tc-file=TESTCONFIG Configuration file to parse and pass to tests
[NOSE_TEST_CONFIG_FILE]

--tc-format=TESTCONFIGFORMAT Test config file format, default is
configparser ini format
[NOSE_TEST_CONFIG_FILE_FORMAT]

--tc=OVERRIDES Option:Value specific overrides.


Passing in an INI configuration file:

$ nosetests -s --tc-file example_cfg.ini

Passing in a YAML configuration file:

$ nosetests -s --tc-file example_cfg.yaml --tc-format yaml

Passing in a Python configuration file:

$ nosetests -s --tc-file example_cfg.py --tc-format python

Overriding a configuration value on the command line:

$ nosetests -s --tc-file example_cfg.ini --tc=myvalue.sub = bar

Overriding multiple key:value pairs:

$ nosetests -s --tc-file example_cfg.ini --tc=myvalue.sub = bar \
--tc=myvalue.sub2 = baz --tc=myvalue.sub3 = bar3


``Warning``: When using the --tc= flag, you can pass it in as many times as
you want to override as many keys/values as needed, however you can not use it
to add in new keys: The configuration key must already be defined. The format
is in ``parent.child = value`` format - the periods are translated into keys
within the config dict.


Changes & News
--------------

0.1
~~~

Initial release. May contain bits of glass.