trait AssertRedirectTrait in Redirect 8

trait AssertRedirectTrait {

  /**
   * Asserts the redirect from $path to the $expected_ending_url.
   *
   * @param string $path
   *   The request path.
   * @param $expected_ending_url
   *   The path where we expect it to redirect. If NULL value provided, no
   *   redirect is expected.
   * @param int $expected_ending_status
   *   The status we expect to get with the first request.
   * @param string $method
   *   The HTTP METHOD to use.
   *
   * @return \Psr\Http\Message\ResponseInterface
   *   The HTTP response.
   */
  public function assertRedirect($path, $expected_ending_url, $expected_ending_status = 301, $method = 'GET') {
    $client = $this
      ->getHttpClient();

    /** @var \Psr\Http\Message\ResponseInterface $response */
    $url = $this
      ->getAbsoluteUrl($path);
    try {
      $response = $client
        ->request($method, $url, [
        'allow_redirects' => false,
      ]);
    } catch (ClientException $e) {
      $this
        ->assertEquals($expected_ending_status, $e
        ->getResponse()
        ->getStatusCode());
      return $e
        ->getResponse();
    }
    $this
      ->assertEquals($expected_ending_status, $response
      ->getStatusCode());
    $ending_url = $response
      ->getHeader('location');
    $ending_url = $ending_url ? $ending_url[0] : NULL;
    $message = "Testing redirect from {$path} to {$expected_ending_url}. Ending url: {$ending_url}";
    if ($expected_ending_url == '<front>') {
      $expected_ending_url = Url::fromUri('base:')
        ->setAbsolute()
        ->toString();
    }
    elseif (!empty($expected_ending_url)) {

      // Check for absolute/external urls.
      if (!parse_url($expected_ending_url, PHP_URL_SCHEME)) {
        $expected_ending_url = Url::fromUri('base:' . $expected_ending_url)
          ->setAbsolute()
          ->toString();
      }
    }
    else {
      $expected_ending_url = NULL;
    }
    $this
      ->assertEqual($expected_ending_url, $ending_url, $message);
    return $response;
  }

}