1. 单元测试Junit

1.1 什么是单元测试？（掌握）

1.2 Junit的特点？（掌握）

1.3 基本用法：（掌握）

实际开发中单元测试的使用方式（掌握）

public class TestDemo {
    public int addMethod(int a,int b){
        return a+b;
    }
}

public class Main {
    @Test
    public void method(){
        TestDemo testDemo = new TestDemo();
        int result = testDemo.addMethod(3, 4);

        Assert.assertEquals("add方法错了",result,7);
    }
}

public class Main {


    @Before
    public void beforeMethod() throws IOException {
        //先备份
        File src = new File("a.txt");
        File dest = new File("b.txt");

        FileInputStream fis = new FileInputStream(src);
        FileOutputStream fos = new FileOutputStream(dest);

        int b;
        while ((b=fis.read())!=-1){
            fos.write(b);
        }
        fos.close();
        fis.close();
    }

    @Test
    public void testMethod(){
        File file = new File("a.txt");
        //删除文件
        boolean result = file.delete();
        //文件是否存在
        boolean exists = file.exists();

        //只有同时满足了，才表示delete方法正确
        Assert.assertEquals("delete方法错了",result,true);
        Assert.assertEquals("delete方法错了",exists,false);
    }

    @After
    public void afterMethod() throws IOException {
        //还原数据
        File dest = new File("a.txt");
        File src = new File("b.txt");

        FileInputStream fis = new FileInputStream(src);
        FileOutputStream fos = new FileOutputStream(dest);

        int b;
        while ((b=fis.read())!=-1){
            fos.write(b);
        }
        fos.close();
        fis.close();

        //删除备份数据
        src.delete();
    }
}