ACP2E-3993: GraphQl invalid discount calculation

Author: abukatar

app/code/Magento/CatalogGraphQl/Model/Resolver/Product/Price/Discount.php

@@ -72,7 +72,10 @@ private function getPriceDifferenceAsValue(float $regularPrice, float $finalPric
      */
     private function getPriceDifferenceAsPercent(float $regularPrice, float $finalPrice): float
     {
-        $difference = $this->getPriceDifferenceAsValue($regularPrice, $finalPrice);
+        $difference = $regularPrice - $finalPrice;
+        if ($difference <= $this->zeroThreshold) {
+            return 0;
+        }
 
         if ($difference <= $this->zeroThreshold || $regularPrice <= $this->zeroThreshold) {
             return 0;

app/code/Magento/CatalogRule/Model/Indexer/ProductPriceCalculator.php

@@ -56,6 +56,6 @@ public function calculate($ruleData, $productData = null)
                 $productPrice = 0;
         }
 
-        return $this->priceCurrency->round($productPrice);
+        return $this->priceCurrency->roundPrice($productPrice, 4);
     }
 }

app/code/Magento/CatalogRule/Pricing/Price/CatalogRulePrice.php

@@ -97,7 +97,7 @@ public function getValue()
                 $this->value = $this->value ? (float)$this->value : false;
             }
             if ($this->value) {
-                $this->value = $this->priceCurrency->convertAndRound($this->value);
+                $this->value = $this->priceCurrency->convertAndRound($this->value, null, null, 4);
             }
         }
 

app/code/Magento/Tax/Model/Calculation/UnitBaseCalculator.php

@@ -56,7 +56,7 @@ protected function calculateWithTaxInPrice(QuoteDetailsItemInterface $item, $qua
 
         // Calculate $priceInclTax
         $applyTaxAfterDiscount = $this->config->applyTaxAfterDiscount($this->storeId);
-        $priceInclTax = $this->calculationTool->round($item->getUnitPrice());
+        $priceInclTax = $item->getUnitPrice();
         if (!$this->isSameRateAsStore($rate, $storeRate)) {
             $priceInclTax = $this->calculatePriceInclTax($priceInclTax, $storeRate, $rate, $round);
         }