MAGETWO-85643: Add price calculation improvement for product option value price #11563

 - Merge Pull Request magento/magento2#11563 from marinagociu/magento2:fix-custom-option-price
 - Merged commits:
   1. 33aa293e
   2. 7ff22bf3

app/code/Magento/Catalog/Model/Product/Option/Value.php

@@ -11,6 +11,7 @@ namespace Magento\Catalog\Model\Product\Option;
 use Magento\Catalog\Model\Product;
 use Magento\Catalog\Model\Product\Option;
 use Magento\Framework\Model\AbstractModel;
+use Magento\Catalog\Pricing\Price\BasePrice;
 
 /**
  * Catalog product option select type model
@@ -224,7 +225,7 @@ class Value extends AbstractModel implements \Magento\Catalog\Api\Data\ProductCu
     public function getPrice($flag = false)
     {
         if ($flag && $this->getPriceType() == self::TYPE_PERCENT) {
-            $basePrice = $this->getOption()->getProduct()->getFinalPrice();
+            $basePrice = $this->getOption()->getProduct()->getPriceInfo()->getPrice(BasePrice::PRICE_CODE)->getValue();
             $price = $basePrice * ($this->_getData(self::KEY_PRICE) / 100);
             return $price;
         }

app/code/Magento/Catalog/Test/Unit/Model/Product/Option/ValueTest.php

@@ -164,13 +164,27 @@ class ValueTest extends \PHPUnit\Framework\TestCase
     private function getMockedProduct()
     {
         $mockBuilder = $this->getMockBuilder(\Magento\Catalog\Model\Product::class)
-            ->setMethods(['getFinalPrice', '__wakeup'])
+            ->setMethods(['getPriceInfo', '__wakeup'])
             ->disableOriginalConstructor();
         $mock = $mockBuilder->getMock();
 
-        $mock->expects($this->any())
-            ->method('getFinalPrice')
-            ->will($this->returnValue(10));
+        $priceInfoMock = $this->getMockForAbstractClass(
+            \Magento\Framework\Pricing\PriceInfoInterface::class,
+            [],
+            '',
+            false,
+            false,
+            true,
+            ['getPrice']
+        );
+
+        $priceMock = $this->getMockForAbstractClass(\Magento\Framework\Pricing\Price\PriceInterface::class);
+
+        $priceInfoMock->expects($this->any())->method('getPrice')->willReturn($priceMock);
+
+        $mock->expects($this->any())->method('getPriceInfo')->willReturn($priceInfoMock);
+
+        $priceMock->expects($this->any())->method('getValue')->willReturn(10);
 
         return $mock;
     }