/**
  * {@inheritdoc}
  */
 public function getTreeModelInstance()
 {
     $pluginInfo = $this->pluginList->getNext($this->subjectType, 'getTreeModelInstance');
     if (!$pluginInfo) {
         return parent::getTreeModelInstance();
     } else {
         return $this->___callPlugins('getTreeModelInstance', func_get_args(), $pluginInfo);
     }
 }
 public function testGetTreeModelInstance()
 {
     $model = $this->_model->getTreeModelInstance();
     $this->assertInstanceOf('Magento\\Catalog\\Model\\ResourceModel\\Category\\Tree', $model);
     $this->assertSame($model, $this->_model->getTreeModelInstance());
 }