MAGETWO-91679: Bundled SKUs are being assembled based on the product ID number

- Fixed an issue with incorrect genereation of dynamic SKU for bundle products;

Author: Alexey Yakimovich

app/code/Magento/Bundle/Model/Product/Type.php

@@ -308,8 +308,11 @@ public function getSku($product)
                 $selectionIds = $this->serializer->unserialize($customOption->getValue());
                 if (!empty($selectionIds)) {
                     $selections = $this->getSelectionsByIds($selectionIds, $product);
-                    foreach ($selections->getItems() as $selection) {
-                        $skuParts[] = $selection->getSku();
+                    foreach ($selectionIds as $selectionId) {
+                        $entity = $selections->getItemByColumnValue('selection_id', $selectionId);
+                        if ($entity->getEntityId()) {
+                            $skuParts[] = $entity->getSku();
+                        }
                     }
                 }
             }

app/code/Magento/Bundle/Test/Unit/Model/Product/TypeTest.php

@@ -1595,7 +1595,7 @@ public function testGetSkuWithoutType()
             ->disableOriginalConstructor()
             ->getMock();
         $selectionItemMock = $this->getMockBuilder(\Magento\Framework\DataObject::class)
-            ->setMethods(['getSku', '__wakeup'])
+            ->setMethods(['getSku', 'getEntityId', '__wakeup'])
             ->disableOriginalConstructor()
             ->getMock();
 
@@ -1623,9 +1623,12 @@ public function testGetSkuWithoutType()
             ->will($this->returnValue($serializeIds));
         $selectionMock = $this->getSelectionsByIdsMock($selectionIds, $productMock, 5, 6);
         $selectionMock->expects(($this->any()))
-            ->method('getItems')
-            ->will($this->returnValue([$selectionItemMock]));
-        $selectionItemMock->expects($this->any())
+            ->method('getItemByColumnValue')
+            ->will($this->returnValue($selectionItemMock));
+        $selectionItemMock->expects($this->at(0))
+            ->method('getEntityId')
+            ->will($this->returnValue(1));
+        $selectionItemMock->expects($this->once())
             ->method('getSku')
             ->will($this->returnValue($itemSku));