Fatal error: Uncaught Error: Interface 'Gloudemans\Shoppingcart\Contracts\Buyable' not found in C:\xampp\htdocs\enercard\vendor\gloudemans\shoppingcart\tests\Fixtures\BuyableProduct.php:7 Stack trace: #0 {main} thrown in C:\xampp\htdocs\enercard\vendor\gloudemans\shoppingcart\tests\Fixtures\BuyableProduct.php on line 7