@Override
    public Stadium findById(final Long id) {
        return stadiumRepository.findById(id);
    }
@Test
    void findById는_존재하지_않는_경기장_요청에_예외를_반환한다() {
        // given
        final Long stadiumId = -999L;

        // when
        // then
        assertThatThrownBy(() -> stadiumReadService.findById(stadiumId))
                .isInstanceOf(StadiumNotFoundException.class);
    }