test: Add verification for correct order of root nodes in MultipleTree traversal.

tests/NestedSetsBehaviorTest.php

@@ -2276,47 +2276,42 @@ public function testChildrenMethodRequiresOrderByForCorrectTreeTraversal(): void
     {
         $this->createDatabase();
 
-        $command = $this->getDb()->createCommand();
-        $xml = $this->loadFixtureXML('test-disorder.xml');
+        $root = new Tree(['name' => 'Root']);
 
-        $children = $xml->children();
+        $root->makeRoot();
 
-        self::assertNotNull(
-            $children,
-            'XML children should not be \'null\'.',
-        );
+        $childB = new Tree(['name' => 'Child B']);
+        $childC = new Tree(['name' => 'Child C']);
+        $childA = new Tree(['name' => 'Child A']);
 
-        foreach ($children as $element => $treeElement) {
-            if ($element === 'tree') {
-                $command->insert(
-                    'tree',
-                    [
-                        'name' => (string) $treeElement['name'],
-                        'lft' => (int) $treeElement['lft'],
-                        'rgt' => (int) $treeElement['rgt'],
-                        'depth' => (int) $treeElement['depth'],
-                    ],
-                )->execute();
-            }
-        }
+        $childB->appendTo($root);
+        $childC->appendTo($root);
+        $childA->appendTo($root);
 
-        $root = Tree::findOne(1);
+        $command = $this->getDb()->createCommand();
 
-        self::assertNotNull(
-            $root,
-            'Root node with ID \'1\' should exist in the database.',
-        );
+        $command->update('tree', ['lft' => 4, 'rgt' => 5], ['name' => 'Child B'])->execute();
+        $command->update('tree', ['lft' => 6, 'rgt' => 7], ['name' => 'Child C'])->execute();
+        $command->update('tree', ['lft' => 2, 'rgt' => 3], ['name' => 'Child A'])->execute();
+        $command->update('tree', ['rgt' => 8], ['name' => 'Root'])->execute();
 
+        $root->refresh();
         $childrenList = $root->children()->all();
-        $expectedOrder = ['Child B', 'Child C', 'Child A'];
+
+        $expectedOrder = ['Child A', 'Child B', 'Child C'];
 
         self::assertCount(
             3,
             $childrenList,
-            'Children list should contain exactly 3 elements.',
+            'Children list should contain exactly \'3\' elements.',
         );
 
         foreach ($childrenList as $index => $child) {
+            self::assertInstanceOf(
+                Tree::class,
+                $child,
+                "Child at index {$index} should be an instance of \'Tree\'.",
+            );
             if (isset($expectedOrder[$index])) {
                 self::assertEquals(
                     $expectedOrder[$index],

tests/NestedSetsQueryBehaviorTest.php

@@ -70,4 +70,51 @@ public function testThrowLogicExceptionWhenBehaviorIsDetachedFromOwner(): void
 
         $behavior->leaves();
     }
+
+    public function testRootsMethodRequiresOrderByForCorrectTreeTraversal(): void
+    {
+        $this->createDatabase();
+
+        $rootD = new MultipleTree(['name' => 'Root D']);
+        $rootD->makeRoot();
+
+        $rootB = new MultipleTree(['name' => 'Root B']);
+        $rootB->makeRoot();
+
+        $rootA = new MultipleTree(['name' => 'Root A']);
+        $rootA->makeRoot();
+
+        $rootC = new MultipleTree(['name' => 'Root C']);
+        $rootC->makeRoot();
+
+        $rootsList = MultipleTree::find()->roots()->all();
+        $expectedOrder = ['Root D', 'Root B', 'Root A', 'Root C'];
+
+        self::assertCount(
+            4,
+            $rootsList,
+            'Roots list should contain exactly \'4\' elements.',
+        );
+
+        foreach ($rootsList as $index => $root) {
+            self::assertInstanceOf(
+                MultipleTree::class,
+                $root,
+                "Root at index {$index} should be an instance of \'MultipleTree\'.",
+            );
+            self::assertArrayHasKey(
+                $index,
+                $expectedOrder,
+                "Expected order array should have key at index {$index}.",
+            );
+
+            if (isset($expectedOrder[$index])) {
+                self::assertEquals(
+                    $expectedOrder[$index],
+                    $root->getAttribute('name'),
+                    "Root at index {$index} should be {$expectedOrder[$index]} in correct \'id\' order.",
+                );
+            }
+        }
+    }
 }