MQE-2126: Can't modify DataEntity data

dev/tests/functional/tests/MFTF/DevDocs/Data/DeprecatedMessageData.xml

@@ -11,4 +11,7 @@
     <entity name="DeprecatedMessageData" deprecated="Entity is deprecated. Please use 'MessageData'.">
         <data key="message">Introduction to the Magento Functional Testing Framework</data>
     </entity>
+    <entity name="MessageData">
+        <data key="justSomeField">Some data</data>
+    </entity>
 </entities>

dev/tests/functional/tests/MFTF/DevDocs/Data/ExtendMessageData.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+ /**
+  * Copyright © Magento, Inc. All rights reserved.
+  * See COPYING.txt for license details.
+  */
+-->
+
+<entities xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+          xsi:noNamespaceSchemaLocation="../../../../../../../src/Magento/FunctionalTestingFramework/DataGenerator/etc/dataProfileSchema.xsd">
+    <entity name="MessageData">
+        <array key="numbers">
+            <item>Something New</item>
+        </array>
+    </entity>
+</entities>

dev/tests/functional/tests/MFTF/DevDocs/Data/MessageData.xml

@@ -10,5 +10,11 @@
           xsi:noNamespaceSchemaLocation="urn:magento:mftf:DataGenerator/etc/dataProfileSchema.xsd">
     <entity name="MessageData">
         <data key="message">Introduction to the Magento Functional Testing Framework</data>
+        <array key="numbers">
+            <item name="zero">0</item>
+            <item name="one">1</item>
+            <item name="two">2</item>
+            <item name="three">3</item>
+        </array>
     </entity>
 </entities>

dev/tests/functional/tests/MFTF/DevDocs/Test/DevDocsTest.xml

@@ -46,5 +46,10 @@
             <argument name="test" value="{{HelperData.entityField}}" />
             <argument name="entityTest" value="HelperData" />
         </actionGroup>
+
+        <assertEqualsCanonicalizing stepKey="assertMergedArray">
+            <actualResult type="array">{{MessageData.numbers}}</actualResult>
+            <expectedResult type="array">["Something New", "0", "1", "2", "3"]</expectedResult>
+        </assertEqualsCanonicalizing>
     </test>
 </tests>

docs/data.md

@@ -276,6 +276,11 @@ Attributes|Type|Use|Description
 
 `<item>` is an individual piece of data to be passed in as part of the parent `<array>` type.
 
+Attributes|Type|Use|Description
+---|---|---|---
+`name`|string|optional|Key attribute of <item/> entity in which to assign a value. By default numeric key will be generated.
+
+
 <!-- Link Definitions -->
 [`<array>`]: #array-tag
 [`<data>`]: #data-tag

etc/di.xml

@@ -157,6 +157,7 @@
             <argument name="idAttributes" xsi:type="array">
                 <item name="/entities/entity" xsi:type="string">name</item>
                 <item name="/entities/entity/(data|array)" xsi:type="string">key</item>
+                <item name="/entities/entity/array/item" xsi:type="string">name</item>
                 <item name="/entities/entity/requiredEntity" xsi:type="string">type</item>
             </argument>
             <argument name="mergeablePaths" xsi:type="array">

src/Magento/FunctionalTestingFramework/Config/Dom.php

@@ -246,8 +246,8 @@ protected function getNodePathByParent(\DOMElement $node, $parentPath)
         $idAttribute = $this->nodeMergingConfig->getIdAttribute($path);
         if ($idAttribute) {
             foreach (explode('|', $idAttribute) as $idAttributeValue) {
-                if ($value = $node->getAttribute($idAttributeValue)) {
-                    $path .= "[@{$idAttributeValue}='{$value}']";
+                if ($node->hasAttribute($idAttributeValue)) {
+                    $path .= "[@{$idAttributeValue}='" . $node->getAttribute($idAttributeValue) . "']";
                     break;
                 }
             }

src/Magento/FunctionalTestingFramework/DataGenerator/Config/Dom.php

@@ -81,6 +81,13 @@ public function initDom($xml, $filename = null)
             }
         }
 
+        $itemNodes = $dom->getElementsByTagName('item');
+        /** @var \DOMElement $itemNode */
+        foreach ($itemNodes as $itemKey => $itemNode) {
+            if ($itemNode->hasAttribute("name") == false) {
+                $itemNode->setAttribute("name", (string)$itemKey);
+            }
+        }
         return $dom;
     }
 }

src/Magento/FunctionalTestingFramework/DataGenerator/etc/dataProfileSchema.xsd

@@ -118,17 +118,32 @@
 
     <xs:complexType name="arrayType">
         <xs:sequence>
-            <xs:element name="item" type="xs:string" maxOccurs="unbounded" minOccurs="0">
-            <xs:annotation>
-                <xs:documentation>
-                    Individual piece of data to be passed in as part of the parrent array type.
-                </xs:documentation>
-            </xs:annotation>
+            <xs:element name="item" type="itemType" maxOccurs="unbounded" minOccurs="0">
+                <xs:annotation>
+                    <xs:documentation>
+                        Individual piece of data to be passed in as part of the parrent array type.
+                    </xs:documentation>
+                </xs:annotation>
             </xs:element>
         </xs:sequence>
         <xs:attribute type="xs:string" name="key" use="required"/>
     </xs:complexType>
 
+
+    <xs:complexType name="itemType">
+        <xs:simpleContent>
+            <xs:extension base="xs:string">
+                <xs:attribute type="xs:string" name="name" use="optional">
+                    <xs:annotation>
+                        <xs:documentation>
+                            Key attribute of item pair.
+                        </xs:documentation>
+                    </xs:annotation>
+                </xs:attribute>
+            </xs:extension>
+        </xs:simpleContent>
+    </xs:complexType>
+
     <xs:complexType name="requiredEntityType">
         <xs:simpleContent>
             <xs:extension base="xs:string">