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

If it is junit5, Then use @Test The note is in import org.junit.jupiter.api.Test; Class .

@Transactional

have access to @Transactional Add transaction to method , Although the return value is true, But there is no reduction of data in the database

    @Test
    @Transactional
    public void testusers()
    {
        System.out.println(userServiceimpl.removeById(1));
    }

@displayname

@DisplayName(" Test class 1")
public class test {
    @Autowired
    public UserServiceimpl userServiceimpl;
    @Test
    @Transactional
    @DisplayName(" Test class 1 The test method of 1")
    public void testusers()
    {
        System.out.println(userServiceimpl.removeById(2));
    }
}

  Click Run on the class , You can run all the test methods of this class

 @beforeall  @afterall Execute once before or after the execution of all test methods

@beforeeeach @aftereach  Execute before or after the execution of each test method

 @BeforeAll
    public static void beforeall()
    {
        System.out.println(" Execute before all test methods ");
    }
    @AfterAll
    public static void afterall()
    {
        System.out.println(" Execute after all test methods ");
    }
    @BeforeEach
    public  void beforeeach()
    {
        System.out.println(" Execute... Before each test method -----");
    }
    @AfterEach
    public  void aftereach()
    {
        System.out.println(" Execute after each test method +++++");
    }

 @Disabled  When executing the test of the test class , It is forbidden to execute this method

 @Test
    @Disabled
    @DisplayName(" Test class 1 The test method of 1")
    public void test1()
    {
        System.out.println(" Test method 1 ");
    }

@Timeout How long to wait , If the arrival time , We're not done yet , Throw an exception

 @Test
    @DisplayName(" Test class 1 The test method of 1")
    @Timeout(value = 500,unit = TimeUnit.MILLISECONDS)
    public void test1() throws Exception
    {
        Thread.sleep(5000);// Setting theory 5000 millisecond , Let the program time out 
        System.out.println(" Test method 1 ");
    }

Assertion , Judge whether the result is consistent with the expectation , If you don't agree, you report an error , It's ok if you agree

//     The previous assertion failed , None of the following code will execute 
    @DisplayName(" Simple assertion tests ")
    @Test
    public void test()
    {
//        The first is hope , The second is practical , The third is the displayed prompt 
      assertEquals(5,4," Business logic ");

      Object o1=new Object();
      Object o2=new Object();
//       Judge whether two objects are equal , The third is the displayed prompt 
      assertSame(o1,o2);
    }

Determine whether the array is consistent

 @Test
    @DisplayName(" Assert test array ")
    void array()
    {
        assertArrayEquals(new int[]{1,2},new int[]{1,3});
    }

Will tell which place is wrong , What should be  

  Combine assertions   Only if all of them are passed

    @Test
    @DisplayName(" Combine assertions ")
    public void all(){
        assertAll(" Combine assertions ",()-> assertTrue(true),()->assertEquals(1,2));
    }

Exception assertion   When the code does not throw an exception, an error is reported , When an exception is thrown, no error is reported

 @DisplayName(" Exception assertion ")
    @Test
    public void testexception()
    {
        assertThrows(ArithmeticException.class,()->{int i=10/2;},"message The code doesn't throw an exception ！！！");
    }

  Stop quickly If the conditions are met , Stop debugging , The code behind it is not executed

    @DisplayName(" Fast failure ")
    @Test
    public void testfail()
    {
        if(1==1)
        {
            fail(" Test to fail ");
        }
    }