feat: update mutation workflow to include 'mutation' group in test framework options and add MutationTest for tree traversal validation.

Author: terabytesoftw

.github/workflows/mutation.yml

@@ -22,7 +22,7 @@ jobs:
     uses: php-forge/actions/.github/workflows/infection.yml@main
     with:
       extensions: pdo, pdo_pgsql, pdo_sqlite
-      framework-options: --test-framework-options="--group=sqlite"
+      framework-options: --test-framework-options="--group=sqlite,mutation"
       hook: |
         # Configurar PostgreSQL con Docker
         docker run -d \

tests/pgsql/MutationTest.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace yii2\extensions\nestedsets\tests\pgsql;
+
+use PHPUnit\Framework\Attributes\Group;
+use yii2\extensions\nestedsets\tests\TestCase;
+
+#[Group('mutation')]
+final class MutationTest extends TestCase
+{
+    public function testChildrenMethodRequiresOrderByForCorrectTreeTraversal(): void
+    {
+        $expectedOrder = ['Child A', 'Child B', 'Child C'];
+
+        $treeStructure = [
+            ['name' => 'Root', 'children' => ['Child B', 'Child C', 'Child A']],
+        ];
+
+        $updates = [
+            ['name' => 'Child B', 'lft' => 4, 'rgt' => 5],
+            ['name' => 'Child C', 'lft' => 6, 'rgt' => 7],
+            ['name' => 'Child A', 'lft' => 2, 'rgt' => 3],
+            ['name' => 'Root', 'rgt' => 8],
+        ];
+
+        $tree = $this->createTreeStructure($treeStructure, $updates);
+        $nodeList = $tree->children()->all();
+
+        $this->assertNodesInCorrectOrder($nodeList, $expectedOrder, 'Child');
+    }
+}