class CsrfTokenRaceTest

class CsrfTokenRaceTest extends WebDriverTestBase {
  
  /**
   * {@inheritdoc}
   */
  protected static $modules = [
    'csrf_race_test',
  ];
  
  /**
   * {@inheritdoc}
   */
  protected $defaultTheme = 'stark';
  
  /**
   * Tests race condition for CSRF tokens for simultaneous requests.
   */
  public function testCsrfRace() {
    $user = $this->createUser([
      'access content',
    ]);
    $this->drupalLogin($user);
    $this->drupalGet('/csrf_race/test');
    $script = '';
    // Delay the request processing of the first request by one second through
    // the request parameter, which will simulate the concurrent processing
    // of both requests.
    foreach ([
      1,
      0,
    ] as $i) {
      $script .= <<<EOT
            jQuery.ajax({
              url: "{<span class="php-variable">$this</span>-&gt;<span class="php-function-or-constant property member-of-self">baseUrl</span>}/csrf_race/get_csrf_token/{<span class="php-variable">$i</span>}",
              method: "GET",
              headers: {
                "Content-Type": "application/json"
              },
              success: function(response) {
                jQuery('body').append("<p class='csrf{<span class="php-variable">$i</span>}'></p>");
                jQuery('.csrf{<span class="php-variable">$i</span>}').html(response);
              },
              error: function() {
                jQuery('body').append('Nothing');
              }
            });
      EOT;
    }
    $this->getSession()
      ->getDriver()
      ->executeScript($script);
    $token0 = $this->assertSession()
      ->waitForElement('css', '.csrf0')
      ->getHtml();
    $token1 = $this->assertSession()
      ->waitForElement('css', '.csrf1')
      ->getHtml();
    $this->assertNotNull($token0);
    $this->assertNotNull($token1);
    $this->assertEquals($token0, $token1);
  }

}