Drush's test suite based on PHPUnit (http://www.phpunit.de/).

Usage
--------
- Install PHPUnit [*]
- Review the configuration settings in phpunit.xml.dist. If customization is needed, copy and rename to phpunit.xml and edit away.
- From the /tests subdirectory, run `phpunit .`

Advanced usage
---------
- Run only tests matching a regex: phpunit --filter=testVersionString .
- Skip slow tests (usually those with network usage): phpunit --exclude-group slow .
- XML results: phpunit --filter=testVersionString --log-junit results.xml .

Reuse by Drush Commandfiles
-----------
Drush commandfiles are encouraged to ship with PHPUnit test cases that
extend Drush_UnitTestCase and Drush_CommandTestCase. In order to run
the tests, you have to point to the /tests/drush_testcase.inc file
such as `phpunit --bootstrap=/path/to/drush/tests/drush_testcase.inc`.
The devel project does exactly this -
http://drupalcode.org/project/devel.git/blob/refs/heads/8.x-1.x:/develDrushTest.php

[*] Install PHPUnit:

Drush requires PHPUnit 3.5 or later; installing with PEAR is easiest.
 
On Linux/OSX:
---------

  sudo apt-get install php5-curl php-pear
  sudo pear upgrade --force PEAR
  sudo pear channel-discover pear.phpunit.de
  sudo pear channel-discover components.ez.no
  sudo pear channel-discover pear.symfony-project.com
  sudo pear install --alldeps phpunit/PHPUnit

On Windows:
-----------

Download and save from go-pear.phar http://pear.php.net/go-pear.phar

  php -q go-pear.phar
  pear channel-discover pear.phpunit.de
  pear channel-discover components.ez.no
  pear channel-discover pear.symfony-project.com
  pear install --alldeps phpunit/PHPUnit
