MAGETWO-53583: "Use Default" checkbox is checked again after saving empty fields (description, name, etc)

- Refactor
- Fixed test

Author: Oleksandr Dubovyk

app/code/Magento/Eav/Model/Entity/Attribute/AbstractAttribute.php

@@ -8,6 +8,7 @@
 
 use Magento\Framework\Api\AttributeValueFactory;
 use Magento\Framework\Exception\LocalizedException;
+use Magento\Framework\Serialize\SerializerInterface;
 
 /**
  * Entity/Attribute/Model - attribute abstract
@@ -116,6 +117,13 @@ abstract class AbstractAttribute extends \Magento\Framework\Model\AbstractExtens
      */
     protected $dataObjectHelper;
 
+    /**
+     * Serializer Instance.
+     *
+     * @var SerializerInterface
+     */
+    private $serializer;
+
     /**
      * Array of attribute types that have empty string as a possible value.
      *
@@ -185,6 +193,22 @@ public function __construct(
         $this->dataObjectHelper = $dataObjectHelper;
     }
 
+    /**
+     * Get Serializer instance.
+     * @deprecated
+     *
+     * @return SerializerInterface
+     */
+    private function getSerializer()
+    {
+        if ($this->serializer === null) {
+            $this->serializer = \Magento\Framework\App\ObjectManager::getInstance()->create(SerializerInterface::class);
+        }
+
+        return $this->serializer;
+    }
+
+
     /**
      * Initialize resource model
      *
@@ -1252,7 +1276,7 @@ public function getValidationRules()
         if (is_array($rules)) {
             return $rules;
         } elseif (!empty($rules)) {
-            return unserialize($rules);
+            return $this->getSerializer()->unserialize($rules);
         }
 
         return [];

app/code/Magento/Eav/Test/Unit/Model/Entity/Attribute/AbstractAttributeTest.php

@@ -144,19 +144,33 @@ public function testGetValidationRulesWhenRuleIsArray()
 
     public function testGetValidationRulesWhenRuleIsSerialized()
     {
-        $objectManagerHelper = new \Magento\Framework\TestFramework\Unit\Helper\ObjectManager($this);
-        $rule = 'some value';
-        $model = $objectManagerHelper->getObject(
-            \Magento\Catalog\Model\Entity\Attribute::class,
-            [
-                'data' => [
-                    \Magento\Eav\Api\Data\AttributeInterface::VALIDATE_RULES => serialize($rule)
-                ]
+        $rule = serialize('some value');
+        $expected = 'some test result';
 
-            ]
-        );
+        $modelClassName = \Magento\Eav\Model\Entity\Attribute\AbstractAttribute::class;
+        $model = $this->getMockForAbstractClass($modelClassName, [], '', false);
 
-        $this->assertEquals($rule, $model->getValidationRules());
+        $serializerMock = $this->getMock(\Magento\Framework\Serialize\SerializerInterface::class);
+
+        $reflection = new \ReflectionClass($modelClassName);
+        $reflectionProperty = $reflection->getProperty('serializer');
+        $reflectionProperty->setAccessible(true);
+        $reflectionProperty->setValue($model, $serializerMock);
+
+        $model->setData(\Magento\Eav\Api\Data\AttributeInterface::VALIDATE_RULES, $rule);
+
+        $serializerMock->method('unserialize')
+            ->with($rule)
+            ->willReturn($expected);
+
+        $this->assertEquals($expected, $model->getValidationRules());
+
+        $data = ['test array'];
+        $model->setData(\Magento\Eav\Api\Data\AttributeInterface::VALIDATE_RULES, $data);
+        $this->assertEquals($data, $model->getValidationRules());
+
+        $model->setData(\Magento\Eav\Api\Data\AttributeInterface::VALIDATE_RULES, null);
+        $this->assertEquals([], $model->getValidationRules());
     }
 
     public function testGetValidationRulesWhenRuleIsEmpty()