public function testIsForbidden()
 {
     $r1 = new \Slim\Http\Response();
     $r2 = new \Slim\Http\Response();
     $r1->setStatus(403);
     $r2->setStatus(500);
     $this->assertTrue($r1->isForbidden());
     $this->assertFalse($r2->isForbidden());
 }