Tests
Unit tests
bin/phpspec run
Integration tests
bin/phpunit -c .
Look at the code, it works with a MailChimp account...
Webhook tests
use ngrok and http://requestb.in/
Debug/dev mode
The best solution to debug or dev environment is to create a free MailChimp account and use the API key of this free "debug/dev" MailChimp account.
We are waiting for a sandbox from MailChimp developer in order to implements a pretty debug/dev mode.