게시판 도메인 모델

package board.domain;

import java.time.LocalDate;

public record PostDraft(
        String authorId,
        String title,
        String content,
        LocalDate publishedOn
) {
    public PostDraft {
        authorId = requireText(authorId, "authorId", 50);
        title = requireText(title, "title", 80);
        content = requireText(content, "content", 720);
        if (publishedOn == null) {
            throw new IllegalArgumentException("publishedOn is required");
        }
    }

    public void validateDate(LocalDate today) {
        if (today == null) {
            throw new IllegalArgumentException("today is required");
        }
        if (publishedOn.isAfter(today)) {
            throw new IllegalArgumentException(
                    "publishedOn must not be in the future");
        }
    }

    private static String requireText(
            String value,
            String field,
            int maxUtf16Units
    ) {
        if (value == null || value.isBlank()) {
            throw new IllegalArgumentException(field + " is required");
        }
        var normalized = value.strip();
        if (normalized.length() > maxUtf16Units) {
            throw new IllegalArgumentException(
                    field + " must be at most " + maxUtf16Units
                            + " UTF-16 code units");
        }
        return normalized;
    }
}

package board.domain;

import java.time.LocalDate;

public record Post(
        long id,
        String authorId,
        String title,
        String content,
        LocalDate publishedOn
) {
    public Post {
        if (id < 1) {
            throw new IllegalArgumentException("id must be positive");
        }
        var checked = new PostDraft(
                authorId, title, content, publishedOn);
        authorId = checked.authorId();
        title = checked.title();
        content = checked.content();
        publishedOn = checked.publishedOn();
    }

    public static Post saved(long id, PostDraft draft) {
        if (draft == null) {
            throw new IllegalArgumentException("draft is required");
        }
        return new Post(
                id,
                draft.authorId(),
                draft.title(),
                draft.content(),
                draft.publishedOn());
    }

    public int contentLength() {
        return content.length();
    }
}

package board.domain;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatThrownBy;

import java.time.LocalDate;
import org.junit.jupiter.api.Test;

class PostDraftTest {
    private final LocalDate today = LocalDate.of(2026, 7, 13);

    @Test
    void 문자열을_정규화하고_유효한_게시글을_만든다() {
        var draft = new PostDraft(
                " member-1 ",
                " Spring MVC ",
                "Spring MVC 요청 흐름을 정리합니다.",
                today);

        draft.validateDate(today);

        assertThat(draft.authorId()).isEqualTo("member-1");
        assertThat(draft.title()).isEqualTo("Spring MVC");
    }

    @Test
    void 본문_길이는_1자부터_720자까지다() {
        assertThat(new PostDraft(
                "member-1", "Java", "a", today).content()).hasSize(1);
        assertThat(new PostDraft(
                "member-1", "Java", "a".repeat(720), today).content())
                .hasSize(720);

        assertThatThrownBy(() -> new PostDraft(
                "member-1", "Java", "", today))
                .isInstanceOf(IllegalArgumentException.class)
                .hasMessage("content is required");
        assertThatThrownBy(() -> new PostDraft(
                "member-1", "Java", "a".repeat(721), today))
                .isInstanceOf(IllegalArgumentException.class);
    }

    @Test
    void 미래_작성일은_거부한다() {
        var tomorrow = today.plusDays(1);
        var draft = new PostDraft(
                "member-1", "HTTP", "HTTP 요청을 정리합니다.", tomorrow);

        assertThatThrownBy(() -> draft.validateDate(today))
                .isInstanceOf(IllegalArgumentException.class)
                .hasMessage("publishedOn must not be in the future");
    }
}

./gradlew test --tests board.domain.PostDraftTest

PostDraftTest > 문자열을_정규화하고_유효한_게시글을_만든다() PASSED
PostDraftTest > 본문_길이는_1자부터_720자까지다() PASSED
PostDraftTest > 미래_작성일은_거부한다() PASSED

public PostDraft {
    if (publishedOn.isAfter(LocalDate.now())) {
        throw new IllegalArgumentException("future date");
    }
}

var clock = Clock.fixed(
        Instant.parse("2026-07-13T00:00:00Z"),
        ZoneOffset.UTC);
var today = LocalDate.now(clock);

draft.validateDate(today);