Issue #3445088: Call to undefined method GuzzleHttp\Utils::defaultUserAgent()

Closes #3445088

src/Tests/TestHttpClientFactory.php

@@ -22,6 +22,8 @@ class TestHttpClientFactory extends ClientFactory {
    *   The HTTP client.
    */
   public function fromOptions(array $config = []) {
+    $default_user_agent = method_exists('GuzzleHttp\Utils' , 'defaultUserAgent') ? Utils::defaultUserAgent() : \GuzzleHttp\default_user_agent();
+
     $default_config = [
       // Security consideration: we must not use the certificate authority
       // file shipped with Guzzle because it can easily get outdated if a
@@ -32,7 +34,7 @@ class TestHttpClientFactory extends ClientFactory {
       'verify' => TRUE,
       'timeout' => 30,
       'headers' => [
-        'User-Agent' => 'Drupal/' . \Drupal::VERSION . ' (+https://www.drupal.org/) ' . Utils::defaultUserAgent(),
+        'User-Agent' => 'Drupal/' . \Drupal::VERSION . ' (+https://www.drupal.org/) ' . $default_user_agent,
       ],
       'handler' => $this->stack,
       // Security consideration: prevent Guzzle from using environment variables