A couple fixes so existing tests pass

Author: jeffreymb

src/Operation/Factory/SubresourceOperationFactory.php

@@ -26,7 +26,7 @@ final class SubresourceOperationFactory implements SubresourceOperationFactoryIn
 {
     const SUBRESOURCE_SUFFIX = '_subresource';
     const FORMAT_SUFFIX = '.{_format}';
-    const ROUTE_OPTIONS = ['defaults' => [], 'requirements' => [], 'options' => [], 'host' => '', 'schemes' => [], 'condition' => '', 'controller' => ''];
+    const ROUTE_OPTIONS = ['defaults' => [], 'requirements' => [], 'options' => [], 'host' => '', 'schemes' => [], 'condition' => '', 'controller' => null];
 
     private $resourceMetadataFactory;
     private $propertyNameCollectionFactory;

tests/Bridge/Symfony/Routing/ApiLoaderTest.php

@@ -203,6 +203,7 @@ private function getApiLoaderWithResourceMetadata(ResourceMetadata $resourceMeta
             'api_platform.action.get_item',
             'api_platform.action.put_item',
             'api_platform.action.delete_item',
+            'api_platform.action.get_subresource',
         ];
         $containerProphecy = $this->prophesize(ContainerInterface::class);