JUnit Annotations: JUnit 5 List with Examples

Why JUnit Is So Popular Among Testers?

JUnit without a doubt, is considered as one of the top Java test frameworks. Below are the pointers behind it.

• Open Source Framework
• Offers integrations with IDEs such as Eclipse, IntelliJ etc. so you could test run your code quickly and easily.
• Offers integration with CI/CD tools such as Jenkins, Teamcity etc. to help you create a sturdy delivery pipeline.
• Offers assertions to help you conveniently compare actual results with the expected results.
• Offers annotations to help you identify the type of test methods.
• Provides a facility to create a test suite which further includes multiple test cases and even other test suites.
• Provides Test Runner to help your easily execute a Test Suite.
• Makes the test code more readable, elegant and increases the quality.
• Provides JUnit Test Report Generation in HTML format.

Execution Sequence Of JUnit Annotations For Selenium

A basic process flowchart of JUnit Annotations that would help you understanding the flow, step by step.

Attributes Used With JUnit Annotations In Selenium WebDriver

These test annotations in JUnit have multiple attributes that can be used for our test method:

1) timeout – To specify timeout for each test case, timeout attribute is specified within @Test annotation. Timeout time is specified in milliseconds. For example, suppose, you know your particular test case takes around 15-20 seconds to get executed and you want your test to fail if it takes more than 20 seconds to get executed, then you can use this attribute as @Test(timeout=20000) for your particular test case. If an execution fails then the progress bar would get red instead of green.

Example:

@Test(timeout=10000)
    public void ExampleCode() throws InterruptedException
    {
            System.setProperty("webdriver.chrome.driver","C:\Users\Lenovo-I7\Desktop\Selenium\chromedriver.exe");
        
        WebDriver driver = new ChromeDriver();
        driver.get("https://www.testmuai.com/");
        driver.manage().window().maximize();
        
        driver.findElement(By.xpath("//*[@id='bs-example-navbar-collapse-1']/ul/li[6]/a")).click();
        Thread.sleep(2000);  //Login Page Button
        
        driver.findElement(By.xpath("//*[@id='app']/section/form/div/div/input[1]")).sendKeys("ramit@lambdatest.com");
            //Username
        
        driver.findElement(By.xpath("//*[@id='app']/section/form/div/div/input[2]")).sendKeys("Hello1234");
        Thread.sleep(2000);  //Password
        
        driver.quit();
    }

-> Now, if you want to put this same timeout for multiple test cases, it is not necessary to add timeout attribute within each and every @Test annotation you have specified in your script. In such case, you can use @Rule annotation to define a global timeout that would be applicable for each @Test method annotation of your script.

Example:

@Rule
public Timeout globalTimeout = Timeout.seconds(10); // 10 seconds max per test method

2) expected – This is a special feature introduced by JUnit 4 which provides the facility to trace an exception that was expected from the execution of a particular code. There are different kinds of exceptions that are probably expected while running a code, such as, NoSuchMethodException, ArithmeticException, IndexOutOfBoundsExceptions etc. For example, you expect occurrence of exception from your code when a particular number is divided by zero, in this case, you would be using ArithmeticException. If the excepted exception does not occur then the test execution will fail.

Example:

@Test(expected= ArithmeticException.class)
    public void ExampleCode() 
      {
            int a= 10,b=0,c;
            
            c=a/b;
            
            System.out.println("Value= " +c);
    }

How Do AI Tools Help Write and Maintain JUnit Annotations?

AI coding assistants speed up JUnit annotation work by generating the boilerplate and catching annotation misuse before a test runs. Four use cases matter most for Selenium test suites.

None of this replaces understanding what each annotation does. It just removes the manual, repetitive part of writing and checking them.

Summarizing It All!

We have covered all the JUnit annotations in Selenium along with their explanation and sample code. We have also performed automated cross browser testing with the help of JUnit annotations in Selenium Grid on a cloud-based cross browser testing tool, TestMu AI.

JUnit annotations are very powerful feature of JUnit, and help to improve code structure by making JUnit tests easier and more readable. Use of these annotations totally depends on your project requirement, using an appropriate annotation at correct place would be very helpful for developers as well as for other team members.

Remember, JUnit annotations for Selenium would only work in JUnit 4 plus versions and would also require to import this particular library, “org.junit.”

Execute your automation script using JUnit annotations on TestMu AI Selenium Grid now! Happy testing. 🙂

JUnit Annotations

JUnit annotations are predefined text elements available in the Java API, assisting the JVM in identifying the intended nature of methods or classes for testing.

In simpler terms, these annotations explicitly indicate methods or classes, attributing specific properties such as testing, disabling tests, ignoring tests, and more. To learn more about JUnit Annotations, follow the video tutorial below!

JUnit 4 Annotations

We will cover JUnit annotations that are well-known to every developer and tester. Below are the JUnit annotations used in JUnit 4.

@BeforeClass: It initializes any object in a running test case. When we instantiate an object in the BeforeClass method, it is only invoked once. The primary function of the @BeforeClass JUnit annotation is to execute some statements before all of the test cases specified in the script.

@BeforeClass
public static void SetUpClass() {
    // Initialization code goes here
    System.out.println("This is @BeforeClass annotation");
}

@Before: This annotation is used whenever we wish to initialize an object during the method's execution. Assuming we have five test cases, the Before method will be called five times before each test method. As a result, it would be invoked every time the test case is run. Test environments are usually set up using this annotation.

@Before
public void SetUp() {
    // Setting up the test environment
    System.out.println("This is @Before annotation");
}

@Test: Attaching @Test to a public void method marks it as a test case. A single automation script can contain many such test methods.

@Test
public void Addition() {
    // Test method for addition
}


@Test
public void Multiplication() {
    // Test method for multiplication
}

@After: Whatever we initialized in the @Before annotation method should be released in the @After annotation method. As a result, this annotation is executed after each test method. The primary function of the @After annotation is to delete temporary data. The TearDown() releases resources or cleans up the test environment in @Before.

@After
public void TearDown() {
    // Cleaning up the test environment
    System.out.println("This is @After annotation");
}

@AfterClass: Anything initialised in @BeforeClass should be released here. It runs once, after all tests finish, and TearDownClass() releases those resources.

@AfterClass
public static void TearDownClass() {
    // Release your resources here
    System.out.println("This is @AfterClass annotation");
}

@Ignore: The @Ignore annotation directs JUnit to skip the execution of the annotated method. This proves useful when a particular code module is unavailable for a specific test case.

The test case is prevented from failing by temporarily placing the concerned code module within the @Ignore annotated method.

In JUnit 4, this annotation provides detailed reporting, helping you keep track of the number of tests that were ignored and the number of tests that ran and failed.

@Ignore
    public void IgnoreMessage()
    {
       String info = "JUnit Annotation Blog" ;
       assertEquals(info,"JUnit Annotation Blog");
       System.out.println("This is @Ignore annotation");
    }

To understand JUnit annotation better, below is the compiled code with output representing all the JUnits annotations in Selenium.

package JUnitAnnotationBlog;

 import static org.junit.Assert.assertEquals;

 import org.junit.After;
 import org.junit.AfterClass;
 import org.junit.Before;
 import org.junit.BeforeClass;
 import org.junit.Ignore;
 import org.junit.Test;

 public class JUnitAnnotations {

     int a=10;
     int b=5;
     Object c;


     @BeforeClass
     public static void SetUpClass()
     {
             //Initialization code goes here
             System.out.println("This is @BeforeClass annotation");
     }


     @Before
     public void SetUp()
     {
             // Setting up the test environment
             System.out.println("This is @Before annotation");
     }


     @Test
     public void Addition()
     {
             c= a+b;
             assertEquals(15,c);
             System.out.println("This is first @Test annotation method= " +c);
     }

     @Test
     public void Multiplication()
     {
             c=a*b;
             assertEquals(50,c);
             System.out.println("This is second @Test annotation method= " +c);
     }


     @After
     public void TearDown()
     {
             // Cleaning up the test environment
             c= null;
             System.out.println("This is @After annotation");
     }


     @AfterClass
     public static void TearDownClass()
     {
             //Release your resources here
             System.out.println("This is @AfterClass annotation");
     }

     @Ignore
     public void IgnoreMessage()
     {
        String info = "JUnit Annotation Blog" ;
        assertEquals(info,"JUnit Annotation Blog");
        System.out.println("This is @Ignore annotation");
     }


 }
 

JUnit 5 renamed most of these annotations and changed how a few behave. The table below maps the JUnit 4 name to its JUnit 5 equivalent.

Junit 5 Annotations

Notably, as of JUnit 5, a significant change is evident, since test classes and methods no longer require public visibility.

Let's now navigate through the key JUnit 5 annotations commonly used.

• @Test : This annotation signifies that a method is a test method. It's important to note that this annotation doesn't take any attributes.

import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;


class JUnit5Test {

    @Test
    void TestNewJUnit5() {
        assertEquals(10, 7+7);
    }
}



• @ParameterizedTest : This annotation enables the execution of a test multiple times with varying arguments. Parameterized tests are defined similarly to regular @Test methods but use the @ParameterizedTest annotation.

In this context, you must declare a source that provides arguments for each invocation used within the test method.

For instance, consider the following example illustrating a parameterized test using the @ValueSource annotation to specify a String array as the source of arguments.




import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.ValueSource;


import static org.junit.jupiter.api.Assertions.assertTrue;


class JUnit5Test {


    @ParameterizedTest
    @ValueSource(strings = { "Kali", "eali", "dani" })
    void endsWithI(String str) {
        assertTrue(str.endsWith("i"));
    }
}



• @RepeatedTest: In JUnit 5, you can repeat a test for a specified number of iterations by annotating a method with @RepeatedTest and indicating the desired total repetitions.

Each iteration of a repeated test functions similarly to the execution of a standard @Test method. This feature proves especially valuable, notably in UI testing scenarios involving Selenium.

Below is a simpler example of repeating a test using flipping a coin:




import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.RepeatedTest;
import org.junit.jupiter.api.RepetitionInfo;
import org.junit.jupiter.api.TestInfo;


import static org.junit.jupiter.api.Assertions.assertTrue;


class CoinFlipTest {


    @RepeatedTest(5)
    @DisplayName("Coin Flip Test")
    void flipCoin(RepetitionInfo repetitionInfo, TestInfo testInfo) {
        String result = flipACoin();


        System.out.println(testInfo.getDisplayName() + " - Result: "+ result);


        // Ensure the result is either "Heads" or "Tails"
        assertTrue(result.equals("Heads") || result.equals("Tails"));
    }


    private String flipACoin() {
        // Simulate flipping a coin and return the result
        return (Math.random() < 0.5) ? "Heads" : "Tails";
    }
}

Here @RepeatedTest simulates flipping a coin five times. The flipCoin method returns Heads or Tails at random, and the test asserts the result is one of the two.



• @DisplayName: This annotation allows test classes and methods to define custom display names, providing more meaningful and descriptive names for test runners and test reports.

import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.TestInfo;


@DisplayName("DisplayName TestMu AI")
class JUnit5Test {
    @Test
    @DisplayName("Custom test name")
    void testWithDisplayName() {
    }


    @Test
    @DisplayName("Print test name")
    void printDisplayName(TestInfo testInfo) {
        System.out.println(testInfo.getDisplayName());
    }
}



• @BeforeEach The @BeforeEach annotation signals that the annotated method should run before each test method, similar to JUnit 4's @Before annotation.

import org.junit.jupiter.api.*;


class JUnit5Test {


    @BeforeEach
    void setUp(TestInfo testInfo) {
        String callingTest = testInfo.getTestMethod().get().getName();
        System.out.println("Initializing for test: " + callingTest);
    }


    @Test
    void firstTest() {
        System.out.println("Executing first test 1");
    }


    @Test
    void secondTest() {
        System.out.println("Executing second test 2");
    }
}



• @AfterEach: The @AfterEach annotation indicates that the annotated method should run after each test method, similar to JUnit 4's @After. This is useful, for instance, if tests require resetting a property after each execution.

import org.junit.jupiter.api.*;


class JUnit5Test {


    @Test
    void firstTest() {
        System.out.println("Executing first test");
    }


    @Test
    void secondTest() {
        System.out.println("Executing second test");
    }


    @AfterEach
    void tearDown(TestInfo testInfo) {
        String callingTest = testInfo.getTestMethod().get().getName();
        System.out.println("Tearing down after test: " + callingTest);
    }
}

In this example, the tearDown() method is annotated with @AfterEach and runs after each test method, providing a way to perform cleanup or reset operations specific to each test.



• @BeforeAll: The @BeforeAll annotation triggers a method to run before all tests, similar to JUnit 4's @BeforeClass. It's commonly used to initialize necessary components for the tests.

import org.junit.jupiter.api.*;
class JUnit5Test {


    @BeforeAll
    static void setUpAll() {
        System.out.println("Initialization before all tests");
    }
    @Test
    void firstTest() {
        System.out.println("Executing first test");
    }
    @Test
    void secondTest() {
        System.out.println("Executing second test");
    }
}



• @AfterAll: The @AfterAll annotation is employed to execute the annotated method after all tests have completed, similar to JUnit 4's @AfterClass. It is useful for tearing down or terminating processes after executing all tests.

import org.junit.jupiter.api.*;
class JUnit5Test {
    @Test
    void firstTest() {
        System.out.println("Executing first test");
    }


    @Test
    void secondTest() {
        System.out.println("Executing second test");
    }
    @AfterAll
    static void tearDownAll() {
        System.out.println("Only run once after all tests");
    }
}

In the above example of this JUnit tutorial, the tearDownAll() method is annotated with @AfterAll and runs once after all tests, providing a mechanism to perform cleanup tasks that are common to all test methods.



• @Tag : The @Tag annotation allows us to assign tags for filtering tests at the class or method-level filtering tests. It is particularly useful when creating test suites with specific categories of tests.

import org.junit.jupiter.api.Tag;
import org.junit.jupiter.api.Test;
@Tag("smoke")
class JUnit5Test {


    @Test
    @Tag("login")
    void validLoginTest() {
        // Test logic for valid login
    }
    @Test
    @Tag("search")
    void searchTest() {
        // Test logic for search functionality
    }
}

In this example, the JUnit 5 Test class is tagged with smoke, and two test methods (validLoginTest and searchTest) are further tagged with login and search, respectively. This allows for selective execution of tests based on the assigned tags, facilitating the creation of focused test suites.




• @Disabled: The @Disabled annotation disables or skips tests, either at the class or method level, similar to JUnit 4's @Ignore.

import org.junit.jupiter.api.Disabled;
import org.junit.jupiter.api.Test;
@Disabled
class DisabledClassDemo {
    @Test
    void testWillBeSkipped() {
        // Test logic to be skipped
    }
}

In this example, the entire class DisabledClassDemo is annotated with @Disabled, causing all @Test methods within the class to be skipped.




import org.junit.jupiter.api.Disabled;
import org.junit.jupiter.api.Test;
class DisabledTestsDemo {
    @Disabled
    @Test
    void testWillBeSkipped() {
        // Test logic to be skipped
    }
  @Test
    void testWillBeExecuted() {
        // Test logic to be executed
    }
}

In this example, the testWillBeSkipped method is individually annotated with @Disabled, leading to the exclusion of only that specific test, while testWillBeExecuted remains enabled and will be executed.