MAGETWO-36857: Abandoned Carts report grid is not displayed

- remove dead code
- unit-test for Magento\Quote\Model\Quote\Item

Author: vkholoshenko

app/code/Magento/Reports/Block/Adminhtml/Shopcart/Product/Grid.php

@@ -16,7 +16,7 @@ class Grid extends \Magento\Reports\Block\Adminhtml\Grid\Shopcart
     /**
      * @var \Magento\Reports\Model\Resource\Quote\CollectionFactory
      */
-    protected $_quoteItemsFactory;
+    protected $quoteItemCollectionFactory;
 
     /**
      * @var \Magento\Quote\Model\QueryResolver
@@ -26,18 +26,18 @@ class Grid extends \Magento\Reports\Block\Adminhtml\Grid\Shopcart
     /**
      * @param \Magento\Backend\Block\Template\Context $context
      * @param \Magento\Backend\Helper\Data $backendHelper
-     * @param \Magento\Reports\Model\Resource\Quote\Item\CollectionFactoryInterface $quoteItemsFactory
+     * @param \Magento\Reports\Model\Resource\Quote\Item\CollectionFactory $quoteItemCollectionFactory
      * @param \Magento\Quote\Model\QueryResolver $queryResolver
      * @param array $data
      */
     public function __construct(
         \Magento\Backend\Block\Template\Context $context,
         \Magento\Backend\Helper\Data $backendHelper,
-        \Magento\Reports\Model\Resource\Quote\Item\CollectionFactoryInterface $quoteItemsFactory,
         \Magento\Quote\Model\QueryResolver $queryResolver,
+        \Magento\Reports\Model\Resource\Quote\Item\CollectionFactory $quoteItemCollectionFactory,
         array $data = []
     ) {
-        $this->_quoteItemsFactory = $quoteItemsFactory;
+        $this->quoteItemCollectionFactory = $quoteItemCollectionFactory;
         $this->queryResolver = $queryResolver;
         parent::__construct($context, $backendHelper, $data);
     }
@@ -57,7 +57,7 @@ protected function _construct()
     protected function _prepareCollection()
     {
         /** @var \Magento\Reports\Model\Resource\Quote\Item\Collection $collection */
-        $collection = $this->_quoteItemsFactory->create();
+        $collection = $this->quoteItemCollectionFactory->create();
         $collection->prepareActiveCartItems();
         $this->setCollection($collection);
         return parent::_prepareCollection();

app/code/Magento/Reports/Model/Resource/Quote/Item/Collection.php

@@ -11,13 +11,6 @@
  */
 class Collection extends \Magento\Framework\Model\Resource\Db\Collection\AbstractCollection
 {
-    const SELECT_COUNT_SQL_TYPE_CART = 1;
-
-    /**
-     * @var int
-     */
-    protected $_selectCountSqlType = 0;
-
     /**
      * Join fields
      *
@@ -26,7 +19,7 @@ class Collection extends \Magento\Framework\Model\Resource\Db\Collection\Abstrac
     protected $_joinedFields = [];
 
     /**
-     * Map
+     * Fields map for correlation names & real selected fields
      *
      * @var array
      */
@@ -55,7 +48,7 @@ class Collection extends \Magento\Framework\Model\Resource\Db\Collection\Abstrac
      * @param \Magento\Catalog\Model\Resource\Product\Collection $productResource
      * @param \Magento\Customer\Model\Resource\Customer $customerResource
      * @param \Magento\Sales\Model\Resource\Order\Collection $orderResource
-     * @param null $connection
+     * @param \Zend_Db_Adapter_Abstract $connection
      * @param \Magento\Framework\Model\Resource\Db\AbstractDb $resource
      */
     public function __construct(
@@ -92,17 +85,6 @@ protected function _construct()
         $this->_init('Magento\Quote\Model\Quote\Item', 'Magento\Quote\Model\Resource\Quote\Item');
     }
 
-    /**
-     * Set type for COUNT SQL select
-     *
-     * @param int $type
-     * @return $this
-     */
-    public function setSelectCountSqlType($type)
-    {
-        $this->_selectCountSqlType = $type;
-        return $this;
-    }
 
     /**
      * Prepare select query for products in carts report
@@ -232,32 +214,6 @@ protected function getCustomerNames($select)
         return $select;
     }
 
-    /**
-     * Resolve customers data based on ids quote table.
-     *
-     * @return void
-     */
-    public function resolveCustomerNames()
-    {
-        $select = $this->customerResource->getReadConnection()->select();
-        $customerName = $select->getAdapter()->getConcatSql(['cust_fname.value', 'cust_lname.value'], ' ');
-
-        $select->from(
-            ['customer' => 'customer_entity']
-        )->columns(
-            ['customer_name' => $customerName]
-        )->where(
-            'customer.entity_id IN (?)',
-            array_column($this->getData(), 'customer_id')
-        );
-        $customersData = $select->getAdapter()->fetchAll($this->getCustomerNames($select));
-
-        foreach ($this->getItems() as $item) {
-            $item->setData(array_merge($item->getData(), current($customersData)));
-            next($customersData);
-        }
-    }
-
     /**
      * Separate query for product and order data
      *