03.基于测试开发讲解和Cobertura框架介绍

首先我们先

CREATE TABLE `t_user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(200) DEFAULT NULL,
  `password` varchar(200) DEFAULT NULL,
  `nickname` varchar(200) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

我们使用jdbc来操作数据库

我们首先导入需要使用到的jar包

接下来我们编写对应的DButils工具

package com.weiyuan.test;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class DBUtils {

    public static Connection getConnection() throws SQLException{
        Connection connection= null;
        connection = DriverManager.getConnection("jdbc:mysql://localhost/test_junit","root","123456");
        return connection;
    }

    public static void  close(Connection connection) {
        if(connection !=null){
            try {
                connection.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    public static void  close(PreparedStatement ps) {
        if(ps !=null){
            try {
                ps.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    public static void  close(ResultSet rs) {
        if(rs !=null){
            try {
                rs.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
}

package com.weiyuan.dao;

import com.fjnu.model.User;

public interface IUserDao {

    public void addUser(User user);

    public void deleteUser(String username);

    public User load(String username);
}

package com.weiyuan.dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.fjnu.model.User;
import com.weiyuan.test.DBUtils;

public class UserDao  implements IUserDao{

    @Override
    public void addUser(User user) {
        // TODO Auto-generated method stub
        Connection connection = null;
        PreparedStatement ps = null;

        try {
            connection = DBUtils.getConnection();
            String sql = "insert into t_user (username,password,nickname) value (?,?,?)";
            ps= connection.prepareStatement(sql);
            ps.setString(1, user.getUsername());
            ps.setString(2, user.getPassword());
            ps.setString(3, user.getNickname());
            ps.executeUpdate();
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            DBUtils.close(connection);
            DBUtils.close(ps);
        }

    }

    @Override
    public void deleteUser(String username) {
        // TODO Auto-generated method stub

    }

    @Override
    public User load(String username) {

        Connection connection = null;
        PreparedStatement ps = null;
        User user = null;
        ResultSet rs = null;
        System.out.println("load is calle");
        try {
            connection = DBUtils.getConnection();
            String sql = "select * from t_user where username = ?";
            ps= connection.prepareStatement(sql);
            ps.setString(1, username);
             rs= ps.executeQuery();
             while(rs.next()){
                 if(user == null){
                     user = new User();
                 }
                 System.out.println("load is222 calle");
                 user.setId(rs.getInt("id"));
                 user.setUsername(rs.getString("username"));
                 user.setPassword(rs.getString("password"));
                 user.setNickname(rs.getString("nickname"));
             }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally{
            DBUtils.close(connection);
            DBUtils.close(ps);
            DBUtils.close(rs);
        }
        return user;
    }

}

接下来是具体的业务实现类

package com.fjnu.service;

import com.fjnu.model.User;

public interface IUserService {
    public void add(User user);

    public void delete(String username);

    public User load(String username);

    public User login(String username, String password);
}

package com.fjnu.service;

import java.util.HashMap;
import java.util.Map;

import com.fjnu.model.User;
import com.weiyuan.dao.UserDao;

public class UserService implements IUserService {

    private UserDao userDao;

    public UserService(UserDao userDao) {
        super();
        this.userDao = userDao;
    }

    public UserService() {
        super();
    }

    @Override
    public void add(User user) {
        // TODO Auto-generated method stub
        if(load(user.getUsername()) != null){
            try {
                throw new Exception("用户名已存在");
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        userDao.addUser(user);
    }

    @Override
    public void delete(String username) {
        // TODO Auto-generated method stub
        userDao.deleteUser(username);
    }

    @Override
    public User load(String username) {
        // TODO Auto-generated method stub
        return userDao.load(username);
    }

    @Override
    public User login(String username, String password) {
        // TODO Auto-generated method stub
        return null;
    }

}

接下来在我们的test下编写我们的业务测试类，包名要和具体的src上的业务在同一个报下package com.fjnu.service;

package com.fjnu.service;

import static org.junit.Assert.*;

import org.junit.Before;
import org.junit.Test;

import com.fjnu.model.User;
import com.weiyuan.dao.UserDao;

public class TestUserService {
    private IUserService us;
    private User baseUser;

    @Before
    public void setUp(){
        // 初始化
        us = new UserService(new UserDao());
        baseUser = new User("admin", "123", "管理员");
    }

    private void assertUserEquals(User u, User tu){
        assertEquals("add方法有错误!", u.getUsername(), tu.getUsername());
        assertEquals("add方法有错误!", u.getNickname(), tu.getNickname());
        assertEquals("add方法有错误!", u.getPassword(), tu.getPassword());
    }

    @Test
    public void testAdd(){
        User u = baseUser;
        us.add(u);
        User tu = us.load("admin");
        assertNotNull(tu);
        assertUserEquals(u, tu);
        //fail("请加入添加的测试代码");
    }

    @Test(expected=Exception.class)
    public void AddExistUsername(){
        us.add(baseUser);
        User tu = new User("admin", "1234", "alskdf");
        us.add(tu);
    }

    @Test
    public void testDelete(){
        us.add(baseUser);
        User tu = us.load(baseUser.getUsername());
        assertNotNull(tu);
        us.delete(baseUser.getUsername());
        tu = us.load(baseUser.getUsername());
        assertNull(tu);
    }

    @Test
    public void testLogin(){
         us.add(baseUser);
        String username=baseUser.getUsername();
        String password=baseUser.getPassword();
        User tu = us.login(username, password);
        assertUserEquals(baseUser, tu);
    }

    @Test(expected=Exception.class)
    public void testNotExistsUserLogin(){
        us.add(baseUser);
        String username="admin1";
        String password="123";
        us.login(username, password);
     }

    @Test(expected=Exception.class)
    public void testPasswordErrorUserLogin(){
        us.add(baseUser);
        String username="admin";
        String password="1235";
        us.login(username, password);
    }
}

这样就完成了测试，但是在测试的过程中会对数据库中的数据产生影响，我们可以使用下面的这种方式来解决

Stub和Mock综述

为何使用Stub和Mock呢？在现实的开发过程中，需要去测试的一个方法并不总是单独存在的，它可能依赖其他方法或者类，比如你要测试service层的逻辑，可能依赖于dao层的数据交互；测试dao层的数据库交互方法，可能会需要去连接数据库。有了Stub和Mock可以降低它们的复杂性，没必要说一定要有数据库连接才能去测试service层的业务逻辑，假如我开发service层的，就没有没必要等同事将DAO层的代码写好，来验证service层的业务逻辑是否正确。

Stub简单介绍

Stub是一个虚拟的物件，一个Stub可以使用最少的依赖方法来模拟该单元测试。简单的说，stub是代码的一部分。在运行时用stub替换真正代码，忽略调用代码的实现。目的是用一个简单一点的行为替换一个复杂的行为，从而独立地测试代码的某一部分。比如，要测试dao层的代码，势必要连接数据库，这时候就可以使用HashMap来模拟数据库操作，这个Stub对象就可以根据你想要的状态去模拟，通过方法去测试Stub的内部状态。可以使用map的方式以及dbUtil来实现stub测试。

package com.weiyuan.dao;

import java.util.HashMap;

import com.fjnu.model.User;

public class UserDaoByHashMapImpl  implements IUserDao{
    private HashMap<String,User> map = new HashMap<>();

    @Override
    public void addUser(User user) {
        // TODO Auto-generated method stub
        map.put(user.getUsername(), user);
    }

    @Override
    public void deleteUser(String username) {
        // TODO Auto-generated method stub
        map.remove(username);
    }

    @Override
    public User load(String username) {
        // TODO Auto-generated method stub
        return map.get(username);
    }

}

我们在测试的时候使用上面创建的类来代替操作真正的数据库