Test Driven Database Development

TDD 로 Database Programming �� 는 방법 & 경��들.
See Also TdddArticle

1002�� 경�� TDD 로 DB 부�� 만들때 ��떻게 ��될까 궁리��던�� 두가��를 ��보��다. 보�� TDD로 DB 부�� 만들때 DB Repository 부�� 대�� MockObject 를 만들��만, 다�� Mock �� 만들고 ��봤다. ��떤 �� 날까를 ��각��며.

~cpp 

import junit.framework.TestCase;

import java.sql.*;

public class SpikeRepositoryTest extends TestCase {
    private Connection con;
    protected IRepository repository;
    private String writer;
    private String title;
    private String body;

    public void setUp() throws SQLException, InstantiationException, IllegalAccessException, ClassNotFoundException {
        initConnection();
        repository= new SpikeRepository(con);
        repository.initialize();

        writer = "writer";
        title = "title";
        body = "body";
    }

    public void tearDown() throws SQLException {
        repository.destroy();
        uninitConnection();
    }

    public void testEdit() throws SQLException {
        repository.createArticle(writer, title, body);
        String writerEdited = "writerEdited";
        String titleEdited = "titleEdited";
        String bodyEdited = "bodyEdited";
        repository.edit(1, writerEdited, titleEdited, bodyEdited);
        Article article = repository.get(1);
        assertEquals (writerEdited, article.getWriter());
        assertEquals (titleEdited, article.getTitle());
        assertEquals (bodyEdited, article.getBody());
    }

    public void testTotalArticle() throws SQLException {
        repository.createArticle(writer, title, body);
        assertEquals (1, repository.getTotalArticle());
    }

    public void testCreateArticle() throws SQLException {
        repository.createArticle(writer, title, body);
        assertEquals (1, repository.getTotalArticle());
    }

    public void testDelete() throws SQLException {
        repository.createArticle(writer, title, body);
        repository.delete(1);
        assertEquals (0, repository.getTotalArticle());
    }

    public void testGet() throws SQLException {
        repository.createArticle(writer, title, body);
        Article article2 = repository.get(1);
        assertEquals(writer, article2.getWriter());
    }

    public void testArticleTableInitialize() throws ClassNotFoundException, IllegalAccessException, InstantiationException, SQLException {
        repository = new SpikeRepository(con);
        repository.initialize();

        String articleTableName = "articlelist";

        String sqlStr="select id, writer, title, body from " + articleTableName;
        PreparedStatement pstmt= con.prepareStatement(sqlStr);
        ResultSet rs = pstmt.executeQuery();

        assertEquals (0, rs.getRow());
    }

    private void initConnection() throws InstantiationException, IllegalAccessException, ClassNotFoundException, SQLException {
        String hostname = "localhost";
        String dbname = "reset";
        String userId = "reset";
        String userPass = "reset";
        Class.forName("com.mysql.jdbc.Driver").newInstance();
        String url="jdbc:mysql://"+hostname+"/"+dbname+"?user="+userId+"&password="+userPass;
        con = DriverManager.getConnection(url);
    }

    private void uninitConnection() throws SQLException {
        con.close();
    }

    public void testDuplicatedInitialize() throws ClassNotFoundException, InstantiationException, IllegalAccessException, SQLException {
        repository.initialize();
        repository.initialize();
        repository.initialize();
        repository.destroy();
    }
}

��는��, DB�� 는 ��드가 �� 드러났다. (��는 �� 긴 ��다. DB �� interface 를 ��더라�� DB �� 드를 �� 가기 �� DB ��드를 ��느�� 다.) �� DB �� 데��를 ��때는 side-effect가 발��므로, ��를 2�� 돌려�� side-effect를 �� 다. ��로 initialize 메��드�� destroy 메��드를 만들고 ��를 setUp, tearDown �� 로 �� side-effect를 ��결��나갔다.

��로그래밍�� 다가, 만�� 기��부�� interface 를 ��뒤�� 꾸로 MockRepository 를 만들 �� 까 ��는 ��각�� 다. (interface 를 ��로�� 같�� 메��드�� 대�� 다른 ��격�� Repository, �� File Based 나 다른 �� 로부�� 데��를 ��는 Repository �� 다�� 각��볼 �� 는 것��다.)
결과는 다�� 문��가 발��다. 바로, interface �� DB Exception 던��것들�� 묻��나는것��다.

~cpp 

import java.sql.SQLException;

public interface IRepository {
    Article get(int index) throws SQLException;

    void initialize() throws SQLException;

    void destroy() throws SQLException;

    void edit(int index, String writer, String title, String body) throws SQLException;

    int getTotalArticle() throws SQLException;

    void createArticle(String writer, String title, String body) throws SQLException;

    void delete(int index);
}

��, MockRepository ��는 Exception �� 던�� 가 ��는데, 메��드��다 ��부 throw 를 던�� 다. (��로는, 다른 ��는 ��관��는데 Java �� Checked Exception �� 문��런�� 모르겠다.

만�� MockRepository를 먼�� 만든다면? interface 를 �� 는 문��가 ��겠��만, 다�� DBRepository 를 만들때가 문��가 된다. interface �� 는 ��를 던�� 므로, interface 를 다�� 던��, ��면 SQL 관련 Exception �� 부 ��당 메��드 �� try-catch 로 ��내�� 다. ��, Database �� 리들�� 대�� 부 Repository �� 결�� 게끔 강��는 ��드가 나��다.

��떤 것�� 바른 ��까. --1002