B2B-2423: Optimize addProductsToCart operations

- CR fixes

Author: Roman Hanin

app/code/Magento/Quote/Test/Unit/Model/QuoteTest.php

@@ -1048,9 +1048,9 @@ public function testAddProductItemPreparation(): void
             ->willReturn(123);
 
         $collectionMock->expects($this->any())
-            ->method('getItemByColumnValue')
+            ->method('getItemsByColumnValue')
             ->with('product_id', 123)
-            ->willReturn($itemMock);
+            ->willReturn([$itemMock]);
 
         $this->quoteItemCollectionFactoryMock->expects($this->once())
             ->method('create')
@@ -1096,7 +1096,7 @@ public function testAddProductItemNew(): void
 
         $productMock = $this->getMockBuilder(Product::class)
             ->addMethods(['getParentProductId', 'setStickWithinParent'])
-            ->onlyMethods(['__wakeup'])
+            ->onlyMethods(['__wakeup', 'getId'])
             ->disableOriginalConstructor()
             ->getMock();
 
@@ -1111,6 +1111,15 @@ public function testAddProductItemNew(): void
             ->method('getIterator')
             ->willReturn($iterator);
 
+        $productMock->expects($this->any())
+            ->method('getId')
+            ->willReturn(123);
+
+        $collectionMock->expects($this->any())
+            ->method('getItemsByColumnValue')
+            ->with('product_id', 123)
+            ->willReturn([$itemMock]);
+
         $this->quoteItemCollectionFactoryMock->expects($this->once())
             ->method('create')
             ->willReturn($collectionMock);