java之 junit单元测试案例【经典版】

一 junit单元测试

1.1 单元测试作用

单元测试要满足AIR原则，即

A： automatic 自动化；

I: Independent 独立性；

R：Repeatable 可重复；

2.单元测试必须使用assert来验证

1.2 案例1 常规单元测试

1.代码

public class CalcDemo
{
    public int add(int x ,int y)
    {
        return x + y;
        //return x * y;
    }

    public int sub(int x ,int y)
    {
        return x - y;
    }
}

2.测试

public class AppTest 

{
    @Test
    void sub()
    {
        CalcDemo calcDemo = new CalcDemo();
        int retValue = calcDemo.sub(2, 2);
        assertEquals(0,retValue);
        System.out.println("");
    }
}

1.3 案例2 单元覆盖率Coverage*

1.代码

public class ScoreDemo
{
    public String scoreLevel(int score)
    {
        if(score <= 0) {
            throw new IllegalArgumentException("缺考");
        } else if (score < 60) {
            return "弱";
        } else if (score < 70) {
            return "差";
        } else if (score <= 80) {
            return "中";
        } else if (score < 90) {
            return "良";
        } else {
            return "优";
        }
    }
}

2.测试

class ScoreDemoTest
{
    @Test
    void scoreLevel()
    {
        ScoreDemo scoreDemo = new ScoreDemo();
        assertEquals("弱",scoreDemo.scoreLevel(52));
    }

    @Test
    void scoreLevelv2()
    {
        ScoreDemo scoreDemo = new ScoreDemo();
        assertEquals("差",scoreDemo.scoreLevel(62));
    }

    @Test
    void scoreLevelv3()
    {
        ScoreDemo scoreDemo = new ScoreDemo();
        assertEquals("中",scoreDemo.scoreLevel(80));
    }

    @Test
    void scoreLevelv4()
    {
        ScoreDemo scoreDemo = new ScoreDemo();
        assertThrows(IllegalArgumentException.class,() -> scoreDemo.scoreLevel(-7));
    }
}

查看测试报告：对应覆盖率

1.4 案例3 BeforeEach，BeforeAfterall

1.代码

public class CalcDemo
{
    public int add(int x ,int y)
    {
        return x + y;
        //return x * y;
    }

    public int sub(int x ,int y)
    {
        return x - y;
    }
}

2.测试

class CalcDemoTestV2
{
    CalcDemo calcDemo = null;

    static StringBuffer stringBuffer = null;

    @BeforeAll
    static void m1()
    {
        stringBuffer = new StringBuffer("abc");
        System.out.println("===============: "+stringBuffer.length());
    }

    @AfterAll
    static void m2()
    {
        System.out.println("===============: "+stringBuffer.append(" ,end").toString());
    }



    @BeforeEach
    void setUp()
    {
        System.out.println("----come in BeforeEach");
        calcDemo = new CalcDemo();
    }

    @AfterEach
    void tearDown()
    {
        System.out.println("----come in AfterEach");
        calcDemo = null;
    }

    @Test
    void add()
    {
        assertEquals(5,calcDemo.add(1,4));
        assertEquals(5,calcDemo.add(2,3));
    }

    @Test
    void sub()
    {
        assertEquals(5,calcDemo.sub(10,5));
    }
}

3.结果

1.5 案例4 junit+反射+注解实现测试

1.定义注解

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface AtguiguTest
{
}

2.定义调用类

public class CalcHelpDemo
{
    public int mul(int x ,int y)
    {
        return x * y;
    }

    @AtguiguTest
    public int div(int x ,int y)
    {
        return x / y;
    }
    @AtguiguTest
    public void thank(int x ,int y)
    {
        System.out.println("3ks，help me test bug");
    }
}

3.定义测试类

@Slf4j
public class AutoTestClient
{
    public static void main(String[] args) throws IOException, ClassNotFoundException, NoSuchMethodException, InvocationTargetException, InstantiationException, IllegalAccessException
    {
        //家庭作业，抽取一个方法，（class，p....）
        CalcHelpDemo calcHelpDemo = new CalcHelpDemo();
        int para1 = 10;
        int para2 = 0;


        Method[] methods = calcHelpDemo.getClass().getMethods();
        AtomicInteger bugCount = new AtomicInteger();
        // 要写入的文件路径（如果文件不存在，会创建该文件）
        String filePath = "BugReport"+ (DateUtil.format(new Date(), "yyyyMMddHHmmss"))+".txt";


        for (int i = 0; i < methods.length; i++)
        {
            if (methods[i].isAnnotationPresent(AtguiguTest.class))
            {
                try
                {
                    methods[i].invoke(calcHelpDemo,para1,para2);//放行
                } catch (Exception e) {
                    bugCount.getAndIncrement();
                    log.info("异常名称:{},异常原因:{}",e.getCause().getClass().getSimpleName(),e.getCause().getMessage());


                    FileUtil.writeString(methods[i].getName()+"\t"+"出现了异常"+"\n", filePath, "UTF-8");
                    FileUtil.appendString("异常名称:"+e.getCause().getClass().getSimpleName()+"\n", filePath, "UTF-8");
                    FileUtil.appendString("异常原因:"+e.getCause().getMessage()+"\n", filePath, "UTF-8");
                }finally {
                    FileUtil.appendString("异常数:"+bugCount.get()+"\n", filePath, "UTF-8");
                }
            }
        }
    }
}

4.查看结果

1.6 案例5 web工程单元测试

1.pom配置

   <!--test-->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
            <!--test-->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
            </dependency>

2.处理类

@Service
public class MemberService
{
    public String add(Integer uid)
    {
        System.out.println("---come in addUser,your uid is: "+uid);
        if (uid == -1)
        {
            throw new IllegalArgumentException("parameter is negative。。。。");
        }
        return "ok";
    }

    public int del(Integer uid)
    {
        System.out.println("---come in del,your uid is: "+uid);

        return uid;
    }
}

3.启动类

@SpringBootApplication
public class App 
{
    public static void main( String[] args )
    {
        SpringApplication.run(App.class, args);
        System.out.println( "Hello World!" );
    }
}

4.测试类

@SpringBootTest
public class MemberTest {
     @Resource //真实调用，落盘mysql-MQ=redis。。。。测试条件充分的情况下
    private MemberService memberService1;

//    @Test
//    void m1()
//    {
//        String result = memberService1.add(2);
//        assertEquals("ok",result);
//
//        System.out.println("----m1 over");
//    }

    @MockBean
    private MemberService memberService2;

//    @Test
//    void m2_NotMockRule()
//    {
//        String result = memberService2.add(2);
//        assertEquals("ok",result);
//
//        System.out.println("----m2_NotMockRule over");
//    }

//    @Test
//    void m2_WithMockRule()
//    {
//        when(memberService2.add(3)).thenReturn("ok");//不真的进入数据库/MQ，不落盘，改变return
//
//        String result = memberService2.add(3);
//        assertEquals("ok",result);
//
//        System.out.println("----m2_WithMockRule over");
//    }
@SpyBean //有规则按照规则走，没有规则走真实
private MemberService memberService3;
    @Test
    void m3()
    {
        when(memberService3.add(2)).thenReturn("ok");
        String result = memberService3.add(2);
        System.out.println("----add result:  "+result);
        Assertions.assertEquals("ok",result);

        int result2 = memberService3.del(3);
        System.out.println("----del result2:  "+result2);
        Assertions.assertEquals(3,result2);

//跨部门调用，不是写代码，累的是心，协调工作。    zzyybs@126.com
        System.out.println("----over");
    }
}

4.结果