public function testNotNotificationWithNullIdThrowsException()
 {
     $request = new Request();
     $request->setMethod('test')->setIsNotification(false)->setId(null);
     $request->setStrictMode(true);
     try {
         $request->getRequestBody();
     } catch (RequestException $e) {
         $this->assertContains('NULL id', $e->getMessage());
         return;
     }
     $this->fail('Expecting exception.');
 }