try to fix tests on old versions

Author: garak

.travis.yml

@@ -5,18 +5,28 @@ php:
     - 5.4
     - 5.5
     - 5.6
-    - 7.0      
+    - 7.0
+    - hhvm
 
+cache:
+    directories:
+        - $HOME/.composer/cache
+
+matrix:
+    fast_finish: true
+    include:
+        - php: 5.3
+          env: COMPOSER_FLAGS="--prefer-lowest"
+        - php: 5.4
+          env: COMPOSER_FLAGS="--prefer-lowest"
+        - php: 5.6
+          env: SYMFONY_VERSION=3.0.*
 
 env:
     - secure: "g+2Ar7a8eAsZtE/mEQT6BWgkx7Bou9qy1381OhI7tMOQBE+KA5Lm+KAC5tH9Us5tmK074dNMsWPBrsgnayxezBjQBpcshDQgoLqaPtWz8XeKTvUEpizFTjQ8v68w42I4SzzMdNIWQhPjiAfjA8e02uaoRELWOYNoc824ot/y1iw="
 
 before_script:
     - echo '' > ~/.phpenv/versions/$(phpenv version-name)/etc/conf.d/xdebug.ini
-    - composer install --prefer-source
+    - composer update $COMPOSER_FLAGS --prefer-dist --no-interaction
     - git config --global user.name travis-ci
     - git config --global user.email travis@example.com
-
-script:
-    - phpunit
-