MAGETWO-50605: Tier pricing is not validated against product special price

Author: magicbunneh

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

@@ -162,6 +162,11 @@ protected function filterTierPrices(array $priceList)
         $qtyCache = [];
         $allCustomersGroupId = $this->groupManagement->getAllCustomersGroup()->getId();
         foreach ($priceList as $priceKey => &$price) {
+            if ($price['price'] >= $this->priceInfo->getPrice(FinalPrice::PRICE_CODE)->getValue()) {
+                unset($priceList[$priceKey]);
+                continue;
+            }
+
             if (isset($price['price_qty']) && $price['price_qty'] == 1) {
                 unset($priceList[$priceKey]);
                 continue;
@@ -204,7 +209,7 @@ protected function getBasePrice()
     public function getSavePercent(AmountInterface $amount)
     {
         return ceil(
-            100 - ((100 / $this->priceInfo->getPrice(RegularPrice::PRICE_CODE)->getAmount()->getBaseAmount())
+            100 - ((100 / $this->priceInfo->getPrice(FinalPrice::PRICE_CODE)->getValue())
                 * $amount->getBaseAmount())
         );
     }