// use Cake\Http\Client;
$http = new Client();

// Status code is `204`
$response = $http->delete('http://example.com', $data, $headers);
$body = $response->getBody();
$this->response = $this->response->withStatus($response->getStatusCode());

// `204` is false
if ($response->isOk()) {
    return 'OK';
}
return 'NG';

// TestCase
$this->enableCsrfToken();
$this->delete('http://example.com', $data);
$this->assertResponseOk(); // `204` is OK