/**
* @expectedException \Magento\Framework\Exception\LocalizedException
* @expectedExceptionMessage User Name is a required field.
* @expectedExceptionMessage First Name is a required field.
* @expectedExceptionMessage Last Name is a required field.
* @expectedExceptionMessage Please enter a valid email.
* @expectedExceptionMessage Password is required field.
* @magentoDbIsolation enabled
*/
public function testBeforeSaveRequiredFieldsValidation()
{
$this->_model->setSomething('some_value');
// force model change
$this->_model->save();
}