update method pay

Author: Babichev Maxim

src/Exceptions/ProductEnded.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace Bavix\Wallet\Exceptions;
+
+class ProductEnded extends \LogicException
+{
+    
+}

src/Traits/CanBePaid.php

@@ -2,6 +2,7 @@
 
 namespace Bavix\Wallet\Traits;
 
+use Bavix\Wallet\Exceptions\ProductEnded;
 use Bavix\Wallet\Interfaces\Product;
 use Bavix\Wallet\Models\Transfer;
 use Illuminate\Database\Eloquent\Model;
@@ -21,6 +22,10 @@ trait CanBePaid
      */
     public function pay(Product $product): Transfer
     {
+        if (!$product->canBuy()) {
+            throw new ProductEnded('The product is out of stock');
+        }
+
         return $this->transfer($product, $product->getAmountProduct(), $product->getMetaProduct());
     }