public function testInstantiation()
{
$response = new NotModified('http://conent-location', 'ofk48fh1ubuc', ['Content-Type' => 'application/json']);
$this->assertEquals(304, $response->getStatusCode());
$this->assertEquals('http://conent-location', $response->headers->get('content-location'));
$this->assertEquals('ofk48fh1ubuc', $response->headers->get('etag'));
}