Tests [are failing](https://travis-ci.org/symfony/symfony/jobs/9542370#L244) with:

```
PHPUnit_Framework_Exception: PHP Strict Standards:  
  Static function Symfony\Component\Validator\Tests\Mapping\Loader\AbstractStaticLoader::loadMetadata() 
  should not be abstract in 
  /home/travis/build/symfony/symfony/src/Symfony/Component/Validator/Tests/Mapping/Loader/StaticMethodLoaderTest.php on line 87
```