protected function setUp() { $elementData = ['group1' => ['id' => 1], 'group2' => ['id' => 2], 'group3' => ['id' => 3]]; $this->_flyweightMock = $this->getMock('Magento\\Config\\Model\\Config\\Structure\\Element\\Group', [], [], '', false); $this->_model = new \Magento\Config\Model\Config\Structure\Element\Iterator($this->_flyweightMock); $this->_model->setElements($elementData, 'scope'); }