Symfony\Component\HttpFoundation\ResponseHeaderBag::set PHP Метод

    public function set($key, $values, $replace = true)
    {
        $uniqueKey = str_replace('_', '-', strtolower($key));

        if ('set-cookie' === $uniqueKey) {
            if ($replace) {
                $this->cookies = array();
            }
            foreach ((array) $values as $cookie) {
                $this->setCookie(Cookie::fromString($cookie));
            }
            $this->headerNames[$uniqueKey] = $key;

            return;
        }

        $this->headerNames[$uniqueKey] = $key;

        parent::set($key, $values, $replace);

        // ensure the cache-control header has sensible defaults
        if (in_array($uniqueKey, array('cache-control', 'etag', 'last-modified', 'expires'))) {
            $computed = $this->computeCacheControlValue();
            $this->headers['cache-control'] = array($computed);
            $this->headerNames['cache-control'] = 'Cache-Control';
            $this->computedCacheControl = $this->parseCacheControl($computed);
        }
    }

 public function it_should_prepare_the_bag(Request $request, Response $response, ResponseHeaderBag $bag)
 {
     $response->headers = $bag;
     $bag->set("content-type", "application/json")->shouldBeCalledTimes(1);
     $this->test($request, $response);
     $this->getBag()->shouldBe(["test" => "Ok"]);
 }