diff --git a/tests/src/Kernel/Normalizer/JsonApiDocumentTopLevelNormalizerTest.php b/tests/src/Kernel/Normalizer/JsonApiDocumentTopLevelNormalizerTest.php
index fb0dd1b..194db8e 100644
--- a/tests/src/Kernel/Normalizer/JsonApiDocumentTopLevelNormalizerTest.php
+++ b/tests/src/Kernel/Normalizer/JsonApiDocumentTopLevelNormalizerTest.php
@@ -8,6 +8,7 @@ use Drupal\Core\Cache\CacheableMetadata;
 use Drupal\Core\Field\FieldStorageDefinitionInterface;
 use Drupal\file\Entity\File;
 use Drupal\jsonapi\JsonApiResource\ErrorCollection;
+use Drupal\jsonapi\JsonApiResource\NullEntityCollection;
 use Drupal\jsonapi\LinkManager\LinkManager;
 use Drupal\jsonapi\JsonApiResource\JsonApiDocumentTopLevel;
 use Drupal\node\Entity\Node;
@@ -396,7 +397,7 @@ class JsonApiDocumentTopLevelNormalizerTest extends JsonapiKernelTestBase {
       ->container
       ->get('jsonapi.serializer_do_not_use_removal_imminent')
       ->serialize(
-        new JsonApiDocumentTopLevel(new ErrorCollection([new BadRequestHttpException('Lorem')]), NULL, []),
+        new JsonApiDocumentTopLevel(new ErrorCollection([new BadRequestHttpException('Lorem')]), new NullEntityCollection(), []),
         'api_json',
         []
       );
@@ -416,7 +417,7 @@ class JsonApiDocumentTopLevelNormalizerTest extends JsonapiKernelTestBase {
    */
   public function testNormalizeConfig() {
     list($request, $resource_type) = $this->generateProphecies('node_type', 'node_type', 'id');
-    $document_wrapper = new JsonApiDocumentTopLevel($this->nodeType, NULL, []);
+    $document_wrapper = new JsonApiDocumentTopLevel($this->nodeType, new NullEntityCollection(), []);
 
     $jsonapi_doc_object = $this
       ->getNormalizer()
@@ -684,7 +685,7 @@ class JsonApiDocumentTopLevelNormalizerTest extends JsonapiKernelTestBase {
       'resource_type' => $resource_type,
       'account' => NULL,
     ];
-    $jsonapi_doc_object = $this->getNormalizer()->normalize(new JsonApiDocumentTopLevel($this->node, NULL, []), 'api_json', $context);
+    $jsonapi_doc_object = $this->getNormalizer()->normalize(new JsonApiDocumentTopLevel($this->node, new NullEntityCollection(), []), 'api_json', $context);
     $this->assertArraySubset($expected_metadata->getCacheTags(), $jsonapi_doc_object->getCacheTags());
     $this->assertArraySubset($expected_metadata->getCacheContexts(), $jsonapi_doc_object->getCacheContexts());
     $this->assertSame($expected_metadata->getCacheMaxAge(), $jsonapi_doc_object->getCacheMaxAge());