.../tests/src/Functional/FileUploadResourceTestBase.php    | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/core/modules/rest/tests/src/Functional/FileUploadResourceTestBase.php b/core/modules/rest/tests/src/Functional/FileUploadResourceTestBase.php
index f06a8ca..564ecaa 100644
--- a/core/modules/rest/tests/src/Functional/FileUploadResourceTestBase.php
+++ b/core/modules/rest/tests/src/Functional/FileUploadResourceTestBase.php
@@ -597,24 +597,16 @@ protected function fileRequest(Url $url, $file_contents, array $headers = []) {
     $url->setOption('query', ['_format' => static::$format]);
 
     $request_options = [];
-    $request_options[RequestOptions::HTTP_ERRORS] = FALSE;
-
-    $request_options['headers'] = $headers + [
+    $request_options[RequestOptions::HEADERS] = $headers + [
       // Set the required (and only accepted) content type for the request.
       'Content-Type' => 'application/octet-stream',
       // Set the required Content-Disposition header for the file name.
       'Content-Disposition' => 'file; filename="example.txt"',
     ];
-
-    $request_options['body'] = $file_contents;
-
+    $request_options[RequestOptions::BODY] = $file_contents;
     $request_options = NestedArray::mergeDeep($request_options, $this->getAuthenticationRequestOptions('POST'));
 
-    $session = $this->getSession();
-    $this->prepareRequest();
-
-    $client = $session->getDriver()->getClient()->getClient();
-    return $client->request('POST', $url->setAbsolute(TRUE)->toString(), $request_options);
+    return $this->request('POST', $url, $request_options);
   }
 
   /**