Composer is now required to install Drush, and more and more Drupal sites are using Composer to manage their modules, themes and Drush extensions. In this session, we'll talk about how these developments are affecting the way Drush works, and how you can make sense out of managing your Drush extensions and configuration, whether you are using Composer, or still running your site without it. We will discuss how Drush fits in to your development workflow, when you may have multiple Drupal sites requiring different versions of Drush, and will also review the relationship between Drush and your Continuous Integration server, and how to best set things up to test with Behat on Travis or Circle CI. Finally, we will go over the impact that Composer and the PHP autoloader have had on the use of classes in Drush core, and Drush extensions.

https://2015.badcamp.net/session/drush-composer-era