[DI] fix failure

Author: nicolas-grekas

Tests/Loader/YamlFileLoaderTest.php

@@ -306,8 +306,11 @@ public function testTaggedArgumentsWithIndex()
         $taggedIterator = new TaggedIteratorArgument('foo', 'barfoo', 'foobar', true);
         $this->assertEquals(new ServiceLocatorArgument($taggedIterator), $container->getDefinition('foo_service_tagged_locator')->getArgument(0));
 
-        $taggedIterator = new TaggedIteratorArgument('foo', null, null, true);
-        $this->assertEquals(new ServiceLocatorArgument($taggedIterator), $container->getDefinition('bar_service_tagged_locator')->getArgument(0));
+        if (is_subclass_of('Symfony\Component\Yaml\Exception\ExceptionInterface', 'Throwable')) {
+            // this test is not compatible with Yaml v3
+            $taggedIterator = new TaggedIteratorArgument('foo', null, null, true);
+            $this->assertEquals(new ServiceLocatorArgument($taggedIterator), $container->getDefinition('bar_service_tagged_locator')->getArgument(0));
+        }
     }
 
     public function testNameOnlyTagsAreAllowedAsString()