From 318425fafd4d92dbabcf89d332dedf9f27978f63 Mon Sep 17 00:00:00 2001
From: Cristiano Casciotti <teknoman84@gmail.com>
Date: Tue, 5 Mar 2019 12:02:18 +0100
Subject: [PATCH 1/3] Fix for issue #21510

---
 app/code/Magento/Indexer/Model/Indexer.php             |  2 +-
 .../Magento/Indexer/Test/Unit/Model/IndexerTest.php    | 10 ++++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/app/code/Magento/Indexer/Model/Indexer.php b/app/code/Magento/Indexer/Model/Indexer.php
index 87a7cce58e1a5..8f3e6b475b466 100644
--- a/app/code/Magento/Indexer/Model/Indexer.php
+++ b/app/code/Magento/Indexer/Model/Indexer.php
@@ -361,7 +361,7 @@ public function getLatestUpdated()
                 return $this->getView()->getUpdated();
             }
         }
-        return $this->getState()->getUpdated();
+        return $this->getState()->getUpdated() ?: '';
     }
 
     /**
diff --git a/app/code/Magento/Indexer/Test/Unit/Model/IndexerTest.php b/app/code/Magento/Indexer/Test/Unit/Model/IndexerTest.php
index 6b7cc12218990..ae0d721a549bd 100644
--- a/app/code/Magento/Indexer/Test/Unit/Model/IndexerTest.php
+++ b/app/code/Magento/Indexer/Test/Unit/Model/IndexerTest.php
@@ -164,7 +164,12 @@ public function testGetLatestUpdated($getViewIsEnabled, $getViewGetUpdated, $get
                 }
             }
         } else {
-            $this->assertEquals($getStateGetUpdated, $this->model->getLatestUpdated());
+            $actualGetLatestUpdated = $this->model->getLatestUpdated();
+            $this->assertEquals($getStateGetUpdated, $actualGetLatestUpdated);
+
+            if ($getStateGetUpdated === null) {
+                $this->assertNotNull($actualGetLatestUpdated);
+            }
         }
     }
 
@@ -182,7 +187,8 @@ public function getLatestUpdatedDataProvider()
             [true, '', '06-Jan-1944'],
             [true, '06-Jan-1944', ''],
             [true, '', ''],
-            [true, '06-Jan-1944', '05-Jan-1944']
+            [true, '06-Jan-1944', '05-Jan-1944'],
+            [false, null, null],
         ];
     }
 

From 486e21c19a6678d3a1b6b0e259408fb1d205bceb Mon Sep 17 00:00:00 2001
From: Cristiano Casciotti <teknoman84@gmail.com>
Date: Tue, 5 Mar 2019 14:27:58 +0100
Subject: [PATCH 2/3] Changed variable name for codacy quality review

---
 app/code/Magento/Indexer/Test/Unit/Model/IndexerTest.php | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/app/code/Magento/Indexer/Test/Unit/Model/IndexerTest.php b/app/code/Magento/Indexer/Test/Unit/Model/IndexerTest.php
index ae0d721a549bd..ca2da9585f934 100644
--- a/app/code/Magento/Indexer/Test/Unit/Model/IndexerTest.php
+++ b/app/code/Magento/Indexer/Test/Unit/Model/IndexerTest.php
@@ -164,11 +164,11 @@ public function testGetLatestUpdated($getViewIsEnabled, $getViewGetUpdated, $get
                 }
             }
         } else {
-            $actualGetLatestUpdated = $this->model->getLatestUpdated();
-            $this->assertEquals($getStateGetUpdated, $actualGetLatestUpdated);
+            $getLatestUpdated = $this->model->getLatestUpdated();
+            $this->assertEquals($getStateGetUpdated, $getLatestUpdated);
 
             if ($getStateGetUpdated === null) {
-                $this->assertNotNull($actualGetLatestUpdated);
+                $this->assertNotNull($getLatestUpdated);
             }
         }
     }

From 0acd6b6a0982941c11f1edfc10afd7896138222e Mon Sep 17 00:00:00 2001
From: nmalevanec <mikola.malevanec@transoftgroup.com>
Date: Fri, 15 Mar 2019 15:22:50 +0200
Subject: [PATCH 3/3] Fix static tests.

---
 app/code/Magento/Indexer/Model/Indexer.php | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/app/code/Magento/Indexer/Model/Indexer.php b/app/code/Magento/Indexer/Model/Indexer.php
index 8f3e6b475b466..2821a46f29416 100644
--- a/app/code/Magento/Indexer/Model/Indexer.php
+++ b/app/code/Magento/Indexer/Model/Indexer.php
@@ -3,6 +3,7 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
+
 namespace Magento\Indexer\Model;
 
 use Magento\Framework\Indexer\ActionFactory;
@@ -14,6 +15,8 @@
 use Magento\Framework\Indexer\StructureFactory;
 
 /**
+ * Indexer model.
+ *
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  */
 class Indexer extends \Magento\Framework\DataObject implements IndexerInterface