Unit test Laravel 4.2 packages in context with Travis CI

.travis.yml

language: php

php:
  - 5.4
  - 5.5
  - 5.6

before_install:
  - composer self-update
  - composer create-project laravel/laravel
  - cd ./laravel
  - composer config repositories.[GITHUB_USERNAME] vcs [GITHUB_HTTPS_CLONE_URL]
  - composer require [PACKAGE_NAME] dev-master
  - composer update
  - cp ./vendor/[GITHUB_USERNAME]/[GITHUB_PACKAGE]/tests/config/app.php ./app/config/testing/
  - export APP_ENV="testing"
  - cd ./vendor/[GITHUB_USERNAME]/[GITHUB_PACKAGE]

script: "phpunit"

app.php

<?php

return array(

    'providers' => append_config(array(
        'Namespace\To\ServiceProvider'
    )),

);