Art4\JsonApiClient\Utils\Helper::parse PHP Method

    public static function parse($json_string)
    {
        $data = static::decodeJson($json_string);
        $manager = new Manager();
        $document = $manager->getFactory()->make('Document', [$manager]);
        $document->parse($data);
        return $document;
    }

 public function testRelationShipToArray()
 {
     $json = '{"data":{"id":"empty-id","type":"invoices","attributes":{"lines":[{"quantity":1,"product_code":17781,"description":"Nordvegen historiesenter (film og utstilling) m\\/mj\\u00f8dsmaking + minikonsert og omvisning Olavskirken","unit_gross_price":"385.00","vat":"0.00"},{"quantity":1,"product_code":17783,"description":"Enkeltrom 3 d\\u00f8gn med konferansepakke, ikke medlem","unit_gross_price":"7190.00","vat":"0.00"},{"quantity":1,"product_code":17785,"description":"Enkeltrom 3 d\\u00f8gn med konferansepakke,  medlem","unit_gross_price":"6690.00","vat":"0.00"},{"quantity":1,"product_code":17795,"description":"Konferanse uten overnatting, utstiller","unit_gross_price":"3690.00","vat":"0.00"}],"order_date":"2016-09-03","recipient":{"city":"sted","email":"*****@*****.**","your_reference":"ref","street1":"Konvallveien 4","name":"Arne AS","zip":"0855"}},"relationships":{"payment_for":{"data":{"type":"person-simple","id":65}}}}}';
     $document = Helper::parse($json);
     $array = $document->asArray(true);
     $this->assertTrue(is_array($array));
 }