function testNoInResponseTo()
 {
     $doc = new \DOMDocument();
     $doc->load(__DIR__ . '/../../../../../../../resources/sample/Response/response02.xml');
     $response = new Response();
     $response->loadFromXml($doc->firstChild);
     $this->assertNull($response->getInResponseTo());
 }
 protected function validateState(Response $response)
 {
     if ($response->getInResponseTo()) {
         $requestState = $this->requestStore->get($response->getInResponseTo());
         if (!$requestState) {
             throw new \RuntimeException('Got response to a request that was not made');
         }
         if ($requestState->getDestination() != $response->getIssuer()) {
             throw new \RuntimeException('Got response from different issuer');
         }
         $this->requestStore->remove($requestState);
     }
 }