diff --git a/core/modules/rest/src/Tests/CreateTest.php b/core/modules/rest/src/Tests/CreateTest.php
index a9db99e..e547c2c 100644
--- a/core/modules/rest/src/Tests/CreateTest.php
+++ b/core/modules/rest/src/Tests/CreateTest.php
@@ -68,23 +68,24 @@ public function testCreate() {
       // Try to create an entity with an access protected field.
       // @see entity_test_entity_field_access()
       if ($entity_type == 'entity_test') {
-        $entity->field_test_text->value = 'no access value';
-        $serialized = $serializer->serialize($entity, $this->defaultFormat, ['account' => $account]);
-        $this->httpRequest('entity/' . $entity_type, 'POST', $serialized, $this->defaultMimeType);
+        $context = ['account' => $account];
+        $normalized = $serializer->normalize($entity, $this->defaultFormat, $context);
+        $normalized['field_test_text'][0]['value'] = 'no access value';
+        $this->httpRequest('entity/' . $entity_type, 'POST', $serializer->serialize($normalized, $this->defaultFormat, $context), $this->defaultMimeType);
         $this->assertResponse(403);
         $this->assertFalse(entity_load_multiple($entity_type, NULL, TRUE), 'No entity has been created in the database.');
 
         // Try to create a field with a text format this user has no access to.
         $entity->field_test_text->value = $entity_values['field_test_text'][0]['value'];
         $entity->field_test_text->format = 'full_html';
-        $serialized = $serializer->serialize($entity, $this->defaultFormat, ['account' => $account]);
+        $serialized = $serializer->serialize($entity, $this->defaultFormat, $context);
         $this->httpRequest('entity/' . $entity_type, 'POST', $serialized, $this->defaultMimeType);
         $this->assertResponse(422);
         $this->assertFalse(entity_load_multiple($entity_type, NULL, TRUE), 'No entity has been created in the database.');
 
         // Restore the valid test value.
         $entity->field_test_text->format = 'plain_text';
-        $serialized = $serializer->serialize($entity, $this->defaultFormat, ['account' => $account]);
+        $serialized = $serializer->serialize($entity, $this->defaultFormat, $context);
       }
 
       // Try to send invalid data that cannot be correctly deserialized.
@@ -98,7 +99,7 @@ public function testCreate() {
       // Try to send invalid data to trigger the entity validation constraints.
       // Send a UUID that is too long.
       $entity->set('uuid', $this->randomMachineName(129));
-      $invalid_serialized = $serializer->serialize($entity, $this->defaultFormat, ['account' => $account]);
+      $invalid_serialized = $serializer->serialize($entity, $this->defaultFormat, $context);
       $response = $this->httpRequest('entity/' . $entity_type, 'POST', $invalid_serialized, $this->defaultMimeType);
       $this->assertResponse(422);
       $error = Json::decode($response);
diff --git a/core/modules/rest/src/Tests/UpdateTest.php b/core/modules/rest/src/Tests/UpdateTest.php
index b27d497..6f58844 100644
--- a/core/modules/rest/src/Tests/UpdateTest.php
+++ b/core/modules/rest/src/Tests/UpdateTest.php
@@ -40,6 +40,8 @@ public function testPatchUpdate() {
     $account = $this->drupalCreateUser($permissions);
     $this->drupalLogin($account);
 
+    $context = ['account' => $account];
+
     // Create an entity and save it to the database.
     $entity = $this->entityCreate($entity_type);
     $entity->save();
@@ -52,7 +54,7 @@ public function testPatchUpdate() {
     $patch_entity = entity_create($entity_type, $patch_values);
     // We don't want to overwrite the UUID.
     unset($patch_entity->uuid);
-    $serialized = $serializer->serialize($patch_entity, $this->defaultFormat, ['account' => $account]);
+    $serialized = $serializer->serialize($patch_entity, $this->defaultFormat, $context);
 
     // Update the entity over the REST API.
     $this->httpRequest($entity->getSystemPath(), 'PATCH', $serialized, $this->defaultMimeType);
@@ -64,7 +66,7 @@ public function testPatchUpdate() {
 
     // Make sure that the field does not get deleted if it is not present in the
     // PATCH request.
-    $normalized = $serializer->normalize($patch_entity, $this->defaultFormat);
+    $normalized = $serializer->normalize($patch_entity, $this->defaultFormat, $context);
     unset($normalized['field_test_text']);
     $serialized = $serializer->encode($normalized, $this->defaultFormat);
     $this->httpRequest($entity->getSystemPath(), 'PATCH', $serialized, $this->defaultMimeType);
@@ -100,8 +102,9 @@ public function testPatchUpdate() {
     $this->assertEqual($entity->field_test_text->value, 'no delete access value', 'Text field was not deleted.');
 
     // Try to update an access protected field.
-    $patch_entity->get('field_test_text')->value = 'no access value';
-    $serialized = $serializer->serialize($patch_entity, $this->defaultFormat, ['account' => $account]);
+    $normalized = $serializer->normalize($patch_entity, $this->defaultFormat, $context);
+    $normalized['field_test_text'][0]['value'] = 'no access value';
+    $serialized = $serializer->serialize($normalized, $this->defaultFormat, $context);
     $this->httpRequest($entity->getSystemPath(), 'PATCH', $serialized, $this->defaultMimeType);
     $this->assertResponse(403);
 
@@ -114,7 +117,7 @@ public function testPatchUpdate() {
       'value' => 'test',
       'format' => 'full_html',
     ));
-    $serialized = $serializer->serialize($patch_entity, $this->defaultFormat, ['account' => $account]);
+    $serialized = $serializer->serialize($patch_entity, $this->defaultFormat, $context);
     $this->httpRequest($entity->getSystemPath(), 'PATCH', $serialized, $this->defaultMimeType);
     $this->assertResponse(422);
 
@@ -139,7 +142,7 @@ public function testPatchUpdate() {
     // Try to send invalid data to trigger the entity validation constraints.
     // Send a UUID that is too long.
     $entity->set('uuid', $this->randomMachineName(129));
-    $invalid_serialized = $serializer->serialize($entity, $this->defaultFormat, ['account' => $account]);
+    $invalid_serialized = $serializer->serialize($entity, $this->defaultFormat, $context);
     $response = $this->httpRequest($entity->getSystemPath(), 'PATCH', $invalid_serialized, $this->defaultMimeType);
     $this->assertResponse(422);
     $error = Json::decode($response);