Fix lowest dependency tests

Author: wouterj

composer.json

@@ -10,6 +10,7 @@
         }
     ],
     "minimum-stability": "dev",
+    "prefer-stable": true,
     "require": {
         "php": ">=5.3.9",
         "symfony-cmf/routing-auto": "~1.1",
@@ -20,7 +21,7 @@
         "jms/metadata": "1.5.*"
     },
     "require-dev": {
-        "symfony-cmf/testing": "~1.2,>=1.2.7",
+        "symfony-cmf/testing": "~1.3",
         "symfony/yaml": "~2.1",
         "matthiasnoback/symfony-dependency-injection-test": "~0.6",
         "matthiasnoback/symfony-config-test": "0.*",