实验五 单元测试
一、实验目的
1）掌握单元测试的方法
2) 学习XUnit测试原理及框架；
3）掌握使用测试框架进行单元测试的方法和过程。
二、实验内容与要求
1、了解单元测试的原理与框架
1.1 单元测试原理
单元测试（unit testing），是指对软件中的最小可测试单元进行检查和验证。对于单元测试中单元的含义，一般来说，要根据实际情况去判定其具体含义，如C语言中单元指一个函数，Java里单元指一个类，图形化的软件中可以指一个窗口或一个菜单等。总的来说，单元就是人为规定的最小的被测功能模块。单元测试是在软件开发过程中要进行的最低级别的测试活动，软件的独立单元将在与程序的其他部分相隔离的情况下进行测试。单元测试是由程序员自己来完成，最终受益的也是程序员自己。可以这么说，程序员有责任编写功能代码，同时也就有责任为自己的代码编写单元测试。执行单元测试，就是为了证明这段代码的行为和我们期望的一致。
单元测试的内容包括
模块接口测试、局部数据结构测试、路径测试、错误处理测试、边界测试
（1）模块接口测试
模块接口测试是单元测试的基础。只有在数据能正确流入、流出模块的前提下，其他测试才有意义。模块接口测试也是集成测试的重点，这里进行的测试主要是为后面打好基础。测试接口正确与否应该考虑下列因素：
-输入的实际参数与形式参数的个数是否相同
-输入的实际参数与形式参数的属性是否匹配
-输入的实际参数与形式参数的量纲是否一致
-调用其他模块时所给实际参数的个数是否与被调模块的形参个数相同；
-调用其他模块时所给实际参数的属性是否与被调模块的形参属性匹配；
-调用其他模块时所给实际参数的量纲是否与被调模块的形参量纲一致；
-调用预定义函数时所用参数的个数、属性和次序是否正确；
-是否存在与当前入口点无关的参数引用；
-是否修改了只读型参数；
-对全程变量的定义各模块是否一致；
-是否把某些约束作为参数传递。
如果模块功能包括外部输入输出，还应该考虑下列因素：
-文件属性是否正确；
-OPEN/CLOSE语句是否正确；
-格式说明与输入输出语句是否匹配；
-缓冲区大小与记录长度是否匹配；
-文件使用前是否已经打开；
-是否处理了文件尾；
-是否处理了输入/输出错误；
-输出信息中是否有文字性错误。
-局部数据结构测试；
-边界条件测试；
-模块中所有独立执行通路测试；
（2）局部数据结构测试
检查局部数据结构是为了保证临时存储在模块内的数据在程序执行过程中完整、正确，局部功能是整个功能运行的基础。重点是一些函数是否正确执行，内部是否运行正确。局部数据结构往往是错误的根源，应仔细设计测试用例，力求发现下面几类错误：
-不合适或不相容的类型说明；
-变量无初值；
-变量初始化或省缺值有错；
-不正确的变量名（拼错或不正确地截断）；
-出现上溢、下溢和地址异常。
（3）边界条件测试
边界条件测试是单元测试中最重要的一项任务。众所周知，软件经常在边界上失效，采用边界值分析技术，针对边界值及其左、右设计测试用例，很有可能发现新的错误。边界条件测试是一项基础测试，也是后面系统测试中的功能测试的重点，边界测试执行的较好，可以大大提高程序健壮性。
（4）独立路径测试
在模块中应对每一条独立执行路径进行测试，单元测试的基本任务是保证模块中每条语句至少执行一次。测试目的主要是为了发现因错误计算、不正确的比较和不适当的控制流造成的错误。具体做法就是程序员逐条调试语句。常见的错误包括：
-误解或用错了算符优先级；
-混合类型运算；
-变量初值错；
-精度不够；
-表达式符号错。
（5）错误处理测试
检查模块的错误处理功能是否包含有错误或缺陷。例如，是否拒绝不合理的输入;出错的描述是否难以理解、是否对错误定位有误、是否出错原因报告有误、是否对错误条件的处理不正确;在对错误处理之前错误条件是否已经引起系统的干预等。
通常单元测试在编码阶段进行。在源程序代码编制完成，经过评审和验证，确认没有语法错误之后，就开始进行单元测试的测试用例设计。利用设计文档，设计可以验证程序功能、找出程序错误的多个测试用例。对于每一组输入，应有预期的正确结果。
1.2 测试框架
xUnit是各种代码驱动测试框架的统称,这些框架可以测试 软件的不同内容(单元),比如函数和类。xUnit框架的主要优点是,它提供了一个自动化测试的解决方案。可以避免多次编写重复的测试代码。
TestCase(具体的测试用例)去使用framwork
TestCase执行后会有TestResult
使用TestSuite控制TestCase的组合
TestRunner执行器，负责执行case
TestListener过程监听，监听case成功失败以及数据结果，输出到结果报告中
1.3 面向特定语言的，基于xUnit框架的自动化测试框架
JUnit是一个开发源代码的Java测试框架，用于编写和运行可重复的测试。他是用于单元测试框架体系xUnit的一个实例（用于java语言）。
实验过程
1.安装Junit
将 JUnit4单元测试包引入这个项目，在属性窗口添加Junit，选择Junit4，如图1、2、3所示。
图1
图2
图3
2. 创建测试用例
生成JUnit测试框架，在Eclipse的Package Explorer中用右键点击该类弹出菜单，选择"JUnit测试用例"。在弹出的对话框中，进行相应的选择，如图4、5、6所示。
图4
图5
图6
3.生命游戏源代码
LifeGame.java
package Game;
import java.util.Random;
public class LifeGame {
public String[][] create(String[][] map,int[] status){
//String[][] map = new String[8][8];
int n=0;
for (int i = 0; i < 8; i++) {
for (int j = 0; j < 8; j++) {
status[n] = new Random().nextInt(2);
if (status[n] == 1)
map[i][j] = "●";
else if (status[n] == 0)
map[i][j] = "○";
n++;
}
}
return map;
}
//该方法检测所有位置，并返回对应位置的point数组
//用point数组，记录对应位置下一轮的状态，1下一代死，2下一代继续活，3下一代复活
public int[] check(String[][] map) {
int n = 0;
int point[] = new int[64];
//统计周围邻居的情况
for (int i = 0; i < 8; i++) {
for (int j = 0; j < 8; j++) {
//用life变量记录周围活着的邻居个数
int life = 0;
//1.判断正下方的位置
if (i + 1 < 8 && map[i + 1][j].equals("●")) {
life++;
}
//2.判断右下位置
if (i + 1 < 8 && j + 1 < 8 && map[i + 1][j + 1].equals("●")) {
life++;
}
//3.判断左下位置
if (i + 1 < 8 && j - 1 >= 0 && map[i + 1][j - 1].equals("●")) {
life++;
}
//4.判断右侧位置
if (j + 1 < 8 && map[i][j + 1].equals("●")) {
life++;
}
//5.判断左侧位置
if (j - 1 >= 0 && map[i][j - 1].equals("●")) {
life++;
}
//6.判断正上方位置
if (i - 1 >= 0 && map[i - 1][j].equals("●")) {
life++;
}
//7.判断右上位置
if (i - 1 >= 0 && j + 1 < 8 && map[i - 1][j + 1].equals("●")) {
life++;
}
//8.判断左上位置
if (i - 1 >= 0 && j - 1 >= 0 && map[i - 1][j - 1].equals("●")) {
life++;
}
//用一个数组，记录对应位置下一轮的状态，1下一代死，2下一代继续活，3下一代复活
if (map[i][j].equals("●")) {
if (life == 1)
point[n] = 1;
else if (life == 2 || life == 3)
point[n] = 2;
else if (life >= 4)
point[n] = 1;
} else {
if (life == 3)
point[n] = 3;
}
n++;
}
}
return point;
}
public String[][] change(String[][] map, int[] point) {
int n = 0;
for (int i = 0; i < 8; i++) {
for (int j = 0; j < 8; j++) {
//变更状态
if (point[n] == 1)
map[i][j] = "○";
if (point[n] == 3)
map[i][j] = "●";
n++;
}
}
return map;
}
public void newMap(String[][] map){
for (int i = 0; i < 8; i++) {
for (int j = 0; j < 8; j++) {
if (j == 7)
System.out.println(map[i][j] + " ");
else
System.out.print(map[i][j] + " ");
}
}
}
}
Main.java
package Game;
import java.util.Random;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
String[][] map = new String[8][8];
int[] status=new int[64];
LifeGame me = new LifeGame();
me.create(map,status);
System.out.println("初始状态为：");
me.newMap(map);
System.out.println("===========");
int n = 0;
int num = 0;//记录变化的次数
while (n == 0) {
//用point数组，记录对应位置下一轮的状态，1下一代死，2下一代继续活，3下一代复活
int[] point = me.check(map);
//获得下一次变化后的图形
map = me.change(map, point).clone();
System.out.println("第" + (++num) + "次变化：");
//打印出来
me.newMap(map);
System.out.println("===========");
System.out.println("输入0继续进行下一步，输入其他数字退出。");
n = new Scanner(System.in).nextInt();
}
}
}
4.单元测试
在LifeGameTest.java中测试check方法，用于计算细胞下一组生命状态；change方法，用于生命游戏细胞状态更新；create方法使用随机函数产生细胞的初始状态。使用记录细胞生命状态和记录细胞下一状态变化的数值为输入参数，与期望的结果进行比较。
testCreate测试用例
expected = {{"○","○","○","●","○","○","○","○"},{"●","○","○","○","○","○","●","●"},
{"○","○","●","○","●","●","○","○"},{"○","○","●","○","○","●","●","○"},
{"○","●","●","○","○","○","○","●"},{"○","○","○","○","●","●","○","○"},
{"●","●","○","●","○","●","○","○"},{"●","●","○","●","○","●","●","○"}};
test1= {0,0,0,1,0,0,0,0,
1,0,0,0,0,0,1,1,
0,0,1,0,1,1,0,0,
0,0,1,0,1,1,0,0,
0,1,1,0,0,0,0,1,
0,0,0,0,1,1,0,0,
1,1,0,1,0,1,0,0,
1,1,0,1,0,1,1,0,};
testCheck测试用例
输入参数teststr的值
{{"○","○","○","●","○","○","○","○"},{"●","○","○","○","○","○","●","●"},
{"○","○","●","○","●","●","○","○"},{"○","○","●","○","○","●","●","○"},
{"○","●","●","○","○","○","○","●"},{"○","○","○","○","●","●","○","○"},
{"●","●","○","●","○","●","○","○"},{"●","●","○","●","○","●","●","○"}};
期望结果expected的值
expected = {0,0,0,0,0,0,0,0,
0,0,0,3,3,3,2,1,
0,3,1,3,2,1,0,3,
0,0,2,0,3,2,2,0,
0,2,2,3,3,0,0,1,
3,0,0,3,2,2,3,0,
2,2,0,2,0,1,0,0,
2,2,0,1,0,2,2,0};
testChange测试用例
输入参数teststr2的值，细胞初状态。
teststr2 = {{"○","○","○","●","○","○","○","○"},{"●","○","○","○","○","○","●","●"},
{"○","○","●","○","●","●","○","○"},{"○","○","●","○","○","●","●","○"},
{"○","●","●","○","○","○","○","●"},{"○","○","○","○","●","●","○","○"},
{"●","●","○","●","○","●","○","○"},{"●","●","○","●","○","●","●","○"}};
输入参数point的值，细胞状态变化。
point = {0,0,0,0,0,0,0,0,
0,0,0,3,3,3,2,1,
0,3,1,3,2,1,0,3,
0,0,2,0,3,2,2,0,
0,2,2,3,3,0,0,1,
3,0,0,3,2,2,3,0,
2,2,0,2,0,1,0,0,
2,2,0,1,0,2,2,0};
期望结果expected的值，细胞更新结果。
expected ={{"○","○","○","●","○","○","○","○"},{"●","○","○","●","●","●","●","○"},
{"○","●","○","●","●","○","○","●"},{"○","○","●","○","●","●","●","○"},
{"○","●","●","●","●","○","○","○"},{"●","○","○","●","●","●","●","○"},
{"●","●","○","●","○","○","○","○"},{"●","●","○","○","○","●","●","○"}};
测试用例代码
LifeGameTest.java
package Game;
//import static org.junit.Assert.*;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
public class LifeGanmeTest {
@Before
public void setUp() throws Exception {
}
@Test
public void testCreate() {
LifeGame me = new LifeGame();
String[][] expected = {{"○","○","○","●","○","○","○","○"},{"●","○","○","○","○","○","●","●"},
{"○","○","●","○","●","●","○","○"},{"○","○","●","○","○","●","●","○"},
{"○","●","●","○","○","○","○","●"},{"○","○","○","○","●","●","○","○"},
{"●","●","○","●","○","●","○","○"},{"●","●","○","●","○","●","●","○"}};
int[] test1= {
0,0,0,1,0,0,0,0,
1,0,0,0,0,0,1,1,
0,0,1,0,1,1,0,0,
0,0,1,0,1,1,0,0,
0,1,1,0,0,0,0,1,
0,0,0,0,1,1,0,0,
1,1,0,1,0,1,0,0,
1,1,0,1,0,1,1,0,};
String[][] point1 =me.create(expected,test1);
Assert.assertArrayEquals(expected, point1);
}
@Test
public void testCheck() {
LifeGame me = new LifeGame();
String[][] teststr = {{"○","○","○","●","○","○","○","○"},{"●","○","○","○","○","○","●","●"},
{"○","○","●","○","●","●","○","○"},{"○","○","●","○","○","●","●","○"},
{"○","●","●","○","○","○","○","●"},{"○","○","○","○","●","●","○","○"},
{"●","●","○","●","○","●","○","○"},{"●","●","○","●","○","●","●","○"}};
int[] point1 =me.check(teststr);
int[] expected = {0,0,0,0,0,0,0,0,
0,0,0,3,3,3,2,1,
0,3,1,3,2,1,0,3,
0,0,2,0,3,2,2,0,
0,2,2,3,3,0,0,1,
3,0,0,3,2,2,3,0,
2,2,0,2,0,1,0,0,
2,2,0,1,0,2,2,0};
Assert.assertArrayEquals(expected, point1);
}
@Test
public void testChange() {
LifeGame me = new LifeGame();
String[][] teststr2 = {{"○","○","○","●","○","○","○","○"},{"●","○","○","○","○","○","●","●"},
{"○","○","●","○","●","●","○","○"},{"○","○","●","○","○","●","●","○"},
{"○","●","●","○","○","○","○","●"},{"○","○","○","○","●","●","○","○"},
{"●","●","○","●","○","●","○","○"},{"●","●","○","●","○","●","●","○"}};
int[] point = {0,0,0,0,0,0,0,0,
0,0,0,3,3,3,2,1,
0,3,1,3,2,1,0,3,
0,0,2,0,3,2,2,0,
0,2,2,3,3,0,0,1,
3,0,0,3,2,2,3,0,
2,2,0,2,0,1,0,0,
2,2,0,1,0,2,2,0};
String[][] expected ={{"○","○","○","●","○","○","○","○"},{"●","○","○","●","●","●","●","○"},
{"○","●","○","●","●","○","○","●"},{"○","○","●","○","●","●","●","○"},
{"○","●","●","●","●","○","○","○"},{"●","○","○","●","●","●","●","○"},
{"●","●","○","●","○","○","○","○"},{"●","●","○","○","○","●","●","○"}};
String[][] point2=me.change(teststr2, point);
Assert.assertArrayEquals(expected, point2);
// assertEquals(true,Arrays.equals(exp_str,me.getNext(teststr2, point)));
}
}
运行结果如图7所示
图7
4.push测试报告和测试代码到各自的github仓库，如图8所示。
图8
思考题：
比较以下二个工匠的做法，你认为哪种好？结合编码和单元测试，谈谈你的认识。
以上两个工匠的做法就是编写代码，测试代码时采取的不同做法，第一种编写代码的同时发现解决问题，需要大量的时间和精力，并且随着代码的不断编写，可能会遇到新的问题。第二种代码编写完成后发现解决问题，可以在测试时发现代码存在的全部问题，一起解决问题将会节省时间。做法因人而异，但第二种做法会节省时间精力。
实验小结
通过本次实验我掌握了单元测试的方法，学习了JUnit测试原理及框架。在使用测试框架进行单元测试的过程中，进一步发现代码中存在的问题。对代码进行重构和优化，使其更加规范。
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