feature #183 Added some integration tests (javiereguiluz)

This PR was squashed before being merged into the 1.0-dev branch (closes #183).

Discussion
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Added some integration tests

In #161 we discussed a bit about integration tests. I know that some people are not very fond of this kind of tests, but the Symfony Installer is a critical piece of our platform and it must always work as expected.

This pull request adds a test which actually builds the PHAR file and test all the different installer options (no Symfony version, special `lts` version, branch version, etc.) It also tests the Symfony Demo application installation. No mocks or tricks are used, so the test actually downloads all the real Symfony packages from the Internet.

Commits
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be61a6b Added some integration tests

Author: javiereguiluz

.travis.yml

@@ -0,0 +1,30 @@
+language: php
+sudo: false
+
+cache:
+  directories:
+    - $HOME/.composer/cache/files
+
+matrix:
+  fast_finish: true
+  include:
+    - php: 5.4
+    - php: 5.5
+    - php: 5.6
+    - php: 7.0
+    - php: hhvm
+  allow_failures:
+    - php: hhvm
+
+before_install:
+  - composer self-update
+  - curl -LSs https://box-project.github.io/box2/installer.php | php
+  - mv box.phar box
+  - chmod 755 box
+
+install:
+  - composer install
+  - php box build
+
+script:
+  - phpunit

composer.json

@@ -20,6 +20,9 @@
         "symfony/filesystem": "~2.5",
         "raulfraile/distill": "~0.9,!=0.9.3,!=0.9.4"
     },
+    "require-dev": {
+        "symfony/process": "~2.5"
+    },
     "extra": {
         "branch-alias": {
             "dev-master": "1.0-dev"