diff --git a/packages/core/src/Observers/OrderLineObserver.php b/packages/core/src/Observers/OrderLineObserver.php
index 91d3fbe700..7486adc21b 100644
--- a/packages/core/src/Observers/OrderLineObserver.php
+++ b/packages/core/src/Observers/OrderLineObserver.php
@@ -15,7 +15,7 @@ class OrderLineObserver
      */
     public function creating(OrderLine $orderLine)
     {
-        if ($orderLine->type != 'shipping' && ! $orderLine->purchasable instanceof Purchasable) {
+        if (! in_array(Purchasable::class, class_implements($orderLine->purchasable_type, true))) {
             throw new NonPurchasableItemException($orderLine->purchasable_type);
         }
     }
@@ -27,7 +27,7 @@ public function creating(OrderLine $orderLine)
      */
     public function updating(OrderLine $orderLine)
     {
-        if ($orderLine->type != 'shipping' && ! $orderLine->purchasable instanceof Purchasable) {
+        if (! in_array(Purchasable::class, class_implements($orderLine->purchasable_type, true))) {
             throw new NonPurchasableItemException($orderLine->purchasable_type);
         }
     }
diff --git a/packages/core/tests/Stubs/DataTypes/TestPurchasable.php b/packages/core/tests/Stubs/DataTypes/TestPurchasable.php
new file mode 100644
index 0000000000..d572b65337
--- /dev/null
+++ b/packages/core/tests/Stubs/DataTypes/TestPurchasable.php
@@ -0,0 +1,139 @@
+<?php
+
+namespace Lunar\Tests\Stubs\DataTypes;
+
+use Illuminate\Support\Collection;
+use Lunar\Base\Purchasable;
+use Lunar\DataTypes\Price;
+use Lunar\Models\TaxClass;
+
+class TestPurchasable implements Purchasable
+{
+    public function __construct(
+        public $name,
+        public $description,
+        public $identifier,
+        public Price $price,
+        public TaxClass $taxClass,
+        public $taxReference = null,
+        public $option = null,
+        public bool $collect = false,
+        public $meta = null
+    ) {
+        //  ..
+    }
+
+    /**
+     * Get the price for the purchasable item.
+     *
+     * @return \Lunar\DataTypes\Price
+     */
+    public function getPrice()
+    {
+        return $this->price;
+    }
+
+    /**
+     * Get prices for the purchasable item.
+     */
+    public function getPrices(): Collection
+    {
+        return collect([
+            $this->price,
+        ]);
+    }
+
+    /**
+     * Return the purchasable unit quantity.
+     */
+    public function getUnitQuantity(): int
+    {
+        return 1;
+    }
+
+    /**
+     * Return the purchasable tax class.
+     */
+    public function getTaxClass(): TaxClass
+    {
+        return $this->taxClass;
+    }
+
+    /**
+     * Return the purchasable tax reference.
+     *
+     * @return string|null
+     */
+    public function getTaxReference()
+    {
+        return $this->taxReference;
+    }
+
+    /**
+     * Return what type of purchasable this is, i.e. physical,digital,shipping.
+     *
+     * @return string
+     */
+    public function getType()
+    {
+        return 'test-purchsable';
+    }
+
+    /**
+     * Return the name for the purchasable.
+     *
+     * @return string
+     */
+    public function getName()
+    {
+        return $this->name;
+    }
+
+    /**
+     * Return the description for the purchasable.
+     *
+     * @return string
+     */
+    public function getDescription()
+    {
+        return $this->description;
+    }
+
+    /**
+     * Return the option for this purchasable.
+     *
+     * @return string|null
+     */
+    public function getOption()
+    {
+        return $this->option;
+    }
+
+    /**
+     * Return a unique string which identifies the purchasable item.
+     *
+     * @return string
+     */
+    public function getIdentifier()
+    {
+        return $this->identifier;
+    }
+
+    /**
+     * Returns whether the purchasable item is shippable.
+     *
+     * @return bool
+     */
+    public function isShippable()
+    {
+        return false;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function getThumbnail()
+    {
+        return null;
+    }
+}