MAGETWO-67509: Decimal to Float Convertion #9266

Author: Oleksii Korshenko

app/code/Magento/Catalog/Pricing/Price/TierPrice.php

@@ -72,7 +72,7 @@ public function __construct(
         Session $customerSession,
         GroupManagementInterface $groupManagement
     ) {
-        $quantity = $quantity ?: 1;
+        $quantity = floatval($quantity) ? $quantity : 1;
         parent::__construct($saleableItem, $quantity, $calculator, $priceCurrency);
         $this->customerSession = $customerSession;
         $this->groupManagement = $groupManagement;