ENGCOM-9100: #32596: Category Update API resets available_sort_by to use config value. #33001

Author: gabrieldagama

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

@@ -1037,7 +1037,7 @@ public function getAvailableSortBy()
     {
         $available = $this->getData(self::KEY_AVAILABLE_SORT_BY);
         if (empty($available)) {
-            return [];
+            return null;
         }
         if ($available && !is_array($available)) {
             $available = explode(',', $available);

dev/tests/api-functional/testsuite/Magento/GraphQl/Catalog/CategoriesQuery/CategoryTreeTest.php

@@ -105,7 +105,7 @@ public function testCategoriesTree()
             $baseCategory['children'][0]['children'][1]['description']
         );
         $this->assertEquals('default-category', $baseCategory['url_key']);
-        $this->assertEquals([], $baseCategory['children'][0]['available_sort_by']);
+        $this->assertEquals(null, $baseCategory['children'][0]['available_sort_by']);
         $this->assertEquals('name', $baseCategory['children'][0]['default_sort_by']);
         $this->assertCount(7, $baseCategory['children']);
         $this->assertCount(2, $baseCategory['children'][0]['children']);
@@ -164,7 +164,7 @@ public function testRootCategoryTree()
             $baseCategory['children'][0]['children'][1]['description']
         );
         $this->assertEquals('default-category', $baseCategory['url_key']);
-        $this->assertEquals([], $baseCategory['children'][0]['available_sort_by']);
+        $this->assertEquals(null, $baseCategory['children'][0]['available_sort_by']);
         $this->assertEquals('name', $baseCategory['children'][0]['default_sort_by']);
         $this->assertCount(7, $baseCategory['children']);
         $this->assertCount(2, $baseCategory['children'][0]['children']);

dev/tests/api-functional/testsuite/Magento/GraphQl/Catalog/CategoryTest.php

@@ -111,7 +111,7 @@ public function testCategoriesTree()
             $responseDataObject->getData('category/url_key')
         );
         self::assertEquals(
-            [],
+            null,
             $responseDataObject->getData('category/children/0/available_sort_by')
         );
         self::assertEquals(
@@ -185,7 +185,7 @@ public function testRootCategoryTree()
             $responseDataObject->getData('category/url_key')
         );
         self::assertEquals(
-            [],
+            null,
             $responseDataObject->getData('category/children/0/available_sort_by')
         );
         self::assertEquals(

dev/tests/integration/testsuite/Magento/Catalog/Model/CategoryTest.php

@@ -273,7 +273,7 @@ public function testGetProductCount(): void
 
     public function testGetAvailableSortBy(): void
     {
-        $this->assertEquals([], $this->_model->getAvailableSortBy());
+        $this->assertEquals(null, $this->_model->getAvailableSortBy());
         $this->_model->setData('available_sort_by', 'test,and,test');
         $this->assertEquals(['test', 'and', 'test'], $this->_model->getAvailableSortBy());
     }