Use a behat specific drush alias

templates/behat.yml.twig

@@ -16,7 +16,7 @@ default:
         password_field: "Password"
         username_field: "Username or e-mail address"
       drush:
-        alias: default.dev
+        alias: default.behat
     Behat\MinkExtension:
       base_url: http://{{ baseurl }}
       goutte: ~