For this to work you need to have your Drush aliasses configured

You also need the path to your Browser app.

alias customer_test_dir='cd path-to/customer_dir'
alias customer_test='customertest_dir ; open -a /Applications/Chromium.app `drush @tst uli --mail=clemens@build2be.nl --no-browser`'

alias composer='php -d memory_limit=-1 `which composer`'