How to develop and test Laravel package in isolation?

I have a Laravel 5.1 application that I've built a couple of custom packages inside of (I follow this tutorial). These packages have no dependencies that didn't already exist in the root Laravel app.

My first question is, if I needed to add a dependency to the package that wasn't already in the root app, how would it get pulled into the root app? Running composer update or composer install from the root application does not pull them in. I understand that once I publish to GitHub and later pull the package into my app with Composer, that it's dependencies will pull in...but how do I do it while developing?

My next question is, how do I go about creating automated tests for this package? None of the tutorials I've found address this. Should the package be in it's own instance of Laravel with the tests inside of the tests directory?

via Chebli Mohamed