public function testRoots()
 {
     $this->assertEquals([1], array_map(function ($value) {
         return $value->id;
     }, Node::find()->roots()->all()));
     $this->assertEquals([1, 26], array_map(function ($value) {
         return $value->id;
     }, MultipleTreeNode::find()->roots()->all()));
 }
 public function testUpdate()
 {
     $node = Node::findOne(3);
     $node->slug = 'update';
     $this->assertEquals(1, $node->update());
 }