Drush aliases not working

aliases.drushrc.php

<?php

$aliases['prod'] = array(
  'uri' => 'example.org',
  'root' => '/var/www/example.org/htdocs',
  'remote-host' => 'example.org',
  'remote-user' => '316e',
  'path-aliases' => array(
    '%files' => 'files/',
    '%dump-dir' => '/tmp',
   ),
);

$aliases['test'] = array(
  'uri' => 'test.example.org',
  'root' => '/var/www/test.example.org/htdocs',
  'remote-host' => 'example.org',
  'remote-user' => '316e',
  'path-aliases' => array(
    '%files' => 'files/',
    '%dump-dir' => '/tmp',
   ),
);

$aliases['dev'] = array(
  'uri' => 'dev.example.org',
  'root' => '/var/www/dev.example.org/htdocs',
  'remote-host' => 'example.org',
  'remote-user' => '316e',
  'path-aliases' => array(
    '%files' => 'files/',
    '%dump-dir' => '/tmp',
   ),
);

shell output

mikey-p ~/git/example.org (master): drush --version
 Drush Version   :  7.0.0-alpha3

mikey-p ~/git/example.org (master): drush @dev status
 Drupal version         :  7.34
 Site URI               :  dev.example.org
 Database driver        :  mysql
 Database hostname      :  localhost
 Database username      :  example
 Database name          :  dev_example
 Database               :  Connected
 Drupal bootstrap       :  Successful
 Drupal user            :  Anonymous
 Default theme          :  example_redesign
 Administration theme   :  seven
 PHP configuration      :  /etc/php.ini
 Drush version          :  5.8
 Drush configuration    :  /var/www/dev.example.org/htdocs/sites/default/dru
                           shrc.php
 Drush alias files      :  /home/316e/.drush/www.aliases.drushrc.php
                           /home/316e/.drush/dev.aliases.drushrc.php
 Drupal root            :  /var/www/dev.example.org/htdocs
 Site path              :  sites/default
 File directory path    :  files
 Temporary file         :  /tmp
 directory path

mikey-p ~/git/example.org (master): composer global update
Changed current directory to /Users/mdp/.composer
Loading composer repositories with package information
Updating dependencies (including require-dev)
  - Updating drush/drush (7.0.0-alpha3 => 7.0.0-alpha4)
    Checking out 37604e786b42ed724dbdd273a62d5198912e28a8

Writing lock file
Generating autoload files
mikey-p ~/git/example.org (master): drush --version
 Drush Version   :  7.0.0-alpha4

mikey-p ~/git/example.org (master): drush cc drush
'drush' cache was cleared.                                                                                                                      [success]
mikey-p ~/git/example.org (master): drush @dev status
The drush command '@dev status' could not be found.  Run `drush cache-clear drush` to clear the commandfile cache if you have installed new     [error]
extensions.
Drush was not able to start (bootstrap) the Drupal database.                                                                                    [error]
Hint: This may occur when Drush is trying to:
 * bootstrap a site that has not been installed or does not have a configured database. In this case you can select another site with a working
database setup by specifying the URI to use with the --uri parameter on the command line. See `drush topic docs-aliases` for details.
 * connect the database through a socket. The socket file may be wrong or the php-cli may have no access to it in a jailed shell. See
http://drupal.org/node/1428638 for details.

Drush was attempting to connect to:
 Drupal version         :  7.34
 Site URI               :  http://default
 PHP executable         :  /usr/local/bin/php
 PHP configuration      :  /usr/local/etc/php/5.6/php.ini
 PHP OS                 :  Darwin
 Drush version          :  7.0.0-alpha4
 Drush temp directory   :  /tmp
 Drush configuration    :  /Users/mdp/git/example.org/sites/default/drushrc.php
 Drush alias files      :  /Users/mdp/.drush/6lzup6cije766.aliases.drushrc.php /Users/mdp/git/example.org/sites/default/aliases.drushrc.php
 Drupal root            :  /Users/mdp/git/example.org
 Site path              :  sites/default


mikey-p ~/git/example.org (master):

We are up to alpha-9. I wonder why composer is giving you alpha 4. Packagist looks OK to me.