private function prepareDomFactoryMock() { $validationStateMock = $this->validationStateMock; $this->domFactoryMock->expects($this->once())->method('createDom')->willReturnCallback(function ($arguments) use($validationStateMock) { return new \Magento\Framework\Config\Dom($arguments['xml'], $validationStateMock, [], null, $arguments['schemaFile']); }); }