JUnit Basic Test cases and Syntax

Introduction

Testing checks whether the application achieves all the requirements, serves the user with expected functionality and the correct use cases. In other words, testing is done to check the application's behavior. The entire code is divided into a few parts based on different properties. These units are called Tests. 

JUnit is an open-source Regression testing framework for Java. A test in JUnit is a method or class used only for testing. These are called Test methods or Tests classes. To define a method as a test method, you can add @Test annotation before it. There are a few other annotations like @After, @Before, @Ignore, etc., in JUnit. Let’s explore what the JUnit test cases are in this article.

JUnit Test cases

JUnit provides essential features like

1. Fixtures
2. Test suites
3. Test runners
4. JUnit classes

The syntax of the JUnit test methods is as follows.

Public class JUnitSyntax {
   @Annotation // Any annotation according to testing requirements
   Public void method() { 
       // Method body
   }
}

You can also try this code with Online Java Compiler

Run Code

The access specifiers like public, private, etc., can be given according to the code requirements, and the tester can choose any return type among all the existing types. 
Let's take a look at basic test cases with code now.

import org.junit.After;             
import org.junit.Before;                     
import org.junit.Test;        

public class JunitAnnotations {    

    @Test        
    public void test() {                  
        System.out.println("Inside @Test annotation method")            
    }                        

    @After        
    public void after() {                            
        System.out.println("Inside @After annotation method");    
    }    

    @Before        
    public void before() {                    
        System.out.println("Inside @Before annotation method");                    
    }    
}

You can also try this code with Online Java Compiler

Run Code

We used the annotations @Test, @After, @Before in the above code to create the test methods. It gives us the following output. 

Output

Inside @Before annotation method 
Inside @Test annotation method 
Inside @After annotation method

• The test method before() with @Before annotation gets executed before all the other methods.
• The method test() with @Test gets executed and prints the output.
• After all the methods are executed, the @After annotation executes the method after().