core/modules/rest/src/Tests/UpdateTest.php | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/core/modules/rest/src/Tests/UpdateTest.php b/core/modules/rest/src/Tests/UpdateTest.php
index 481e790..94cbe2d 100644
--- a/core/modules/rest/src/Tests/UpdateTest.php
+++ b/core/modules/rest/src/Tests/UpdateTest.php
@@ -368,8 +368,16 @@ protected function patchEntity(EntityInterface $entity, array $read_only_fields,
     $serialized = $serializer->serialize($normalized, $format, $context);
 
     $this->httpRequest($url, 'PATCH', $serialized, $mime_type);
-    $this->assertResponse(204);
-    $this->assertResponseBody('');
+    $this->assertResponse(200);
+    $request = Json::decode($serialized);
+    $response = Json::decode($this->responseBody);
+    if ($format === 'hal_json') {
+      unset($request['_links']);
+      unset($response['_links']);
+      unset($response['_embedded']);
+    }
+    $response = array_diff_key($response, array_combine($read_only_fields, $read_only_fields));
+    $this->assertEqual($request, $response);
   }
 
 }