Merge pull request #384 from magento-okapis/MAGETWO-55126-Cannot-link-simple-product-to-configurable-one-2.1.2

Fixed issue:
 - MAGETWO-55126: [Backport] [API] Can not link simple product to configurable one - for 2.1.x

Author: Oleksii Korshenko

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

@@ -22,7 +22,6 @@
  * @method Product setHasError(bool $value)
  * @method \Magento\Catalog\Model\ResourceModel\Product getResource()
  * @method null|bool getHasError()
- * @method Product setAssociatedProductIds(array $productIds)
  * @method array getAssociatedProductIds()
  * @method Product setNewVariationsAttributeSetId(int $value)
  * @method int getNewVariationsAttributeSetId()
@@ -2609,4 +2608,13 @@ private function getMediaGalleryProcessor()
         }
         return $this->mediaGalleryProcessor;
     }
+
+    /**
+     * Set the associated products
+     * @param array $productIds
+     */
+    public function setAssociatedProductIds(array $productIds)
+    {
+        $this->getExtensionAttributes()->setConfigurableProductLinks($productIds);
+    }
 }

app/code/Magento/ConfigurableProduct/Model/LinkManagement.php

@@ -132,7 +132,7 @@ public function removeChild($sku, $childSku)
         if (count($options) == count($ids)) {
             throw new NoSuchEntityException(__('Requested option doesn\'t exist'));
         }
-        $product->addData(['associated_product_ids' => $ids]);
+        $product->setAssociatedProductIds($ids);
         $product->save();
         return true;
     }

app/code/Magento/ConfigurableProduct/Test/Unit/Model/LinkManagementTest.php

@@ -159,7 +159,6 @@ public function testAddChild()
             ->will(
                 $this->returnValue([0 => [1, 2, 3]])
             );
-        $configurable->expects($this->once())->method('__call')->with('setAssociatedProductIds', [[1, 2, 3, 999]]);
         $configurable->expects($this->once())->method('save');
 
         $this->assertTrue(true, $this->object->addChild($productSku, $childSku));
@@ -203,7 +202,7 @@ public function testRemoveChild()
         $childSku = 'simple_10';
 
         $product = $this->getMockBuilder('Magento\Catalog\Model\Product')
-            ->setMethods(['getTypeInstance', 'save', 'getTypeId', 'addData', '__wakeup'])
+            ->setMethods(['getTypeInstance', 'save', 'getTypeId', 'addData', '__wakeup', 'getExtensionAttributes'])
             ->disableOriginalConstructor()
             ->getMock();
 
@@ -231,7 +230,12 @@ public function testRemoveChild()
         $productType->expects($this->once())->method('getUsedProducts')
             ->will($this->returnValue([$option]));
 
-        $product->expects($this->once())->method('addData')->with(['associated_product_ids' => []]);
+        $extensionAttributesMock = $this->getMockBuilder(\Magento\Framework\Api\ExtensionAttributesInterface::class)
+            ->disableOriginalConstructor()
+            ->setMethods(['setConfigurableProductLinks'])
+            ->getMock();
+
+        $product->expects($this->once())->method('getExtensionAttributes')->willReturn($extensionAttributesMock);
         $product->expects($this->once())->method('save');
         $this->assertTrue($this->object->removeChild($productSku, $childSku));
     }