@Test
public void 엔티티매니저로_확인() {

    //given
    Pay pay = payRepository.save(new Pay("test1",  100));
    //when
    String updateTradeNo = "test2";
    payService.updateNative(pay.getId(), updateTradeNo);
    //then
    Pay saved = payRepository.findAll().get(0);
    assertThat(saved.getTradeNo()).isEqualTo(updateTradeNo);
}