MAGETWO-88504: Tiered pricing and quantity Increments do not work with decimal inventory

Author: Oleksandr Iegorov

app/code/Magento/CatalogInventory/Model/Stock/Item.php

@@ -402,7 +402,7 @@ public function getQtyIncrements()
                     $this->qtyIncrements = $this->stockConfiguration->getQtyIncrements($this->getStoreId());
                 } else {
                     $qtyIncrements = $this->getData(static::QTY_INCREMENTS);
-                    $this->qtyIncrements = ($this->getIsQtyDecimal() ? (float) $qtyIncrements : (int) $qtyIncrements);
+                    $this->qtyIncrements = $this->getIsQtyDecimal() ? (float) $qtyIncrements : (int) $qtyIncrements;
                 }
             }
             if ($this->qtyIncrements <= 0) {

app/code/Magento/CatalogInventory/Test/Unit/Model/Stock/ItemTest.php

@@ -394,6 +394,7 @@ public function testGetQtyIncrements($config, $expected)
         $this->setDataArrayValue('qty_increments', $config['qty_increments']);
         $this->setDataArrayValue('enable_qty_increments', $config['enable_qty_increments']);
         $this->setDataArrayValue('use_config_qty_increments', $config['use_config_qty_increments']);
+        $this->setDataArrayValue('is_qty_decimal', $config['is_qty_decimal']);
         if ($config['use_config_qty_increments']) {
             $this->stockConfiguration->expects($this->once())
                 ->method('getQtyIncrements')
@@ -415,26 +416,38 @@ public function getQtyIncrementsDataProvider()
                 [
                     'qty_increments' => 1,
                     'enable_qty_increments' => true,
-                    'use_config_qty_increments' => true
+                    'use_config_qty_increments' => true,
+                    'is_qty_decimal' => false
                 ],
                 1
             ],
             [
                 [
                     'qty_increments' => -2,
                     'enable_qty_increments' => true,
-                    'use_config_qty_increments' => true
+                    'use_config_qty_increments' => true,
+                    'is_qty_decimal' => false
                 ],
                 false
             ],
             [
                 [
                     'qty_increments' => 3,
                     'enable_qty_increments' => true,
-                    'use_config_qty_increments' => false
+                    'use_config_qty_increments' => false,
+                    'is_qty_decimal' => false
                 ],
                 3
             ],
+            [
+                [
+                    'qty_increments' => 0.5,
+                    'enable_qty_increments' => true,
+                    'use_config_qty_increments' => false,
+                    'is_qty_decimal' => true
+                ],
+                0.5
+            ],
         ];
     }