Graphical Java Junit entry case (code)

Detailed explanation of Java's Junit entry case (code)

Go directly to the code demonstration:

For example, you have written an ArrayList Class method:

public class ArrayList implements List { 
    private int size = 0;
    
    private Object[] elementData = new Object[100];
    
    public void add(Object o){
        
    }
    public void add(int index, Object o){
        
    }
    
    public Object get(int index){
        return Object;
    }
    
    public Object remove(int index){
        return Object;
    }
    
    public int size(){
        return -1;
    }  
}

What should I do if I want to test it now? At this time, the Junit tool can be used;

First we create a Junit class:

If you right-click directly on the class you want to test You can directly check the required test methods, such as:

Then you can start adding methods directly:

public class ArrayListTest {

　　 // 这里的@Test是必须的注释，就是告诉JUnit这里就是一个测试方法
    @Test
    public void testGet() {
        static Object[] Data = new Object[]{1,2,3,4,5,6,7,8};
            ArrayList test;
                // 添加数据到test中
                .........
                ......... 

                //测试test 这里要说一下，
                //出了要assertEqual 判断值是否相等的话，其实还有assertFalse，assertNull等方法判断
                assertEqual(Data[1],test.get(1));
    }    
}

Yes, that’s right, it’s that simple. If there is no problem with your class, you should be able to return a picture like this:

However, have you found that if you are testing other methods, such as add and remove, It is necessary to have an ArrayList pre-populated with data. Do I need to do this every time I run a test?

This is too redundant. At this time, JUnit has its own clever trick:

public class ArrayListTest {

    static Object[] Data = new Object[]{1,2,3,4,5,6,7,8};
    ArrayList test;
       
    //这个before注释可以理解成：
    //在执行每个@Test修饰的方法前都先要执行这个setUp，等于前置条件一样
    @Before
    public void setUp() throws Exception{
        test = new ArrayList();
        for(Object data: Data){
            test.add(data);
        }
    }
        //test function ;

}

It seems to be almost OK now, but what should I do when there are multiple test classes, run them one by one? Isn't this similar to creating a main method test?

So Junit provides another test suite group:

//你现在有3个测试类
public class Test1{
    @Test
    public void test(){
        //...Test1
    }
}

public class Test2{
    @Test
    public void test(){
        //...Test2
    }
}
public class Test3{
    @Test
    public void test(){
        //...Test3
    }
}


//创建一个测试套件类（测试套件可以互相叠加的）：
@RunWith(Suite.class)
@Suite.SuiteClasses({test1.class,test2.class,test3.class
                    })
public class SuitTest {
　　//必须是public 修饰的，空类
}

In addition to the comments written above, there are actually quite a few, but I won’t go into them yet. (You are too scumbag to use these, run away...), I will post it for readers to take a look at:

That’s all, it’s just an introduction That’s all. There is no advanced technology or thinking. simple: -/.

I would like to share a sentence at the end:

Test cases are used to prove that you are not wrong, not to prove that you are right.

I personally feel that these words really speak to my heart.

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