public TextAnswer getAnswerByQuestionId(long questionId) {
        if (!textAnswers.containsKey(questionId)) {
            throw new MissingTextAnswerForQuestionException(questionId);
        }
        return textAnswers.get(questionId);
    }
@Test
    void 질문_ID로_서술형_답변을_반환한다() {
        // given
        TextAnswers textAnswers = new TextAnswers(List.of(new TextAnswer(1, "답".repeat(20))));

        // when
        TextAnswer actual = textAnswers.getAnswerByQuestionId(1);

        // then
        assertThat(actual.getContent()).isEqualTo("답".repeat(20));
    }