public function testResetUniqueField() { $uniqueFields = new \ReflectionProperty('Magento\\Framework\\Model\\ResourceModel\\Db\\AbstractDb', '_uniqueFields'); $uniqueFields->setAccessible(true); $uniqueFields->setValue($this->_model, ['uniqueField1', 'uniqueField2']); $this->_model->resetUniqueField(); $this->assertEquals([], $this->_model->getUniqueFields()); }