Symfony\Component\DependencyInjection\Loader\XmlFileLoader::supports PHP Method

    public function supports($resource, $type = null)
    {
        return is_string($resource) && 'xml' === pathinfo($resource, PATHINFO_EXTENSION);
    }

 public function testSupports()
 {
     $loader = new XmlFileLoader(new ContainerBuilder(), new FileLocator());
     $this->assertTrue($loader->supports('foo.xml'), '->supports() returns true if the resource is loadable');
     $this->assertFalse($loader->supports('foo.foo'), '->supports() returns true if the resource is loadable');
 }