[Spring][assertJ] asserThatThrouwBy 테스트 예외처리

    @Test
    public void returnType() {
        Member m1 = new Member("AAA", 10);
        Member m2 = new Member("AAA", 20);
        memberRepository.save(m1);
        memberRepository.save(m2);


        assertThatThrownBy(() -> memberRepository.findOptionalByUsername("AAA")).isInstanceOf(NonUniqueResultException.class);
    }

asserThatThrouwBy를 사용하여 예외를 확인 할 수 있음