Testing is an inseparable part of the software development cycle which involves checking the software at different levels, like unit tests, integration tests, functional tests, system tests, etc. You can perform it either manually or through automation using various tools and frameworks. The choice of testing tools depends on the framework you’re using. For example, if you use a JavaScript framework, you may use JUnit, TestNG, Jasmine, Selenium, and others.

JUnit and TestNG are the two most widely used Java testing frameworks for automation testing. So let’s explore and understand more about them.

 

JUnit Vs TestNG

Here’s a tabular comparison of the key features between JUnit and TestNG. They mainly differ in their features and functionality.

 

Features	JUnit	TestNG
Framework	JUnit is an open-source unit testing framework	TestNG is an open-source testing framework
Annotations	Don’t support advanced annotations (like @BeforeGroups, @AfterGroups) and these are limited as compared to TestNG	Supports advanced, unique, and more extensive sets of annotations
Parallel Execution	It doesn’t have in-built support for parallel execution of tests.	It provides in-built support for parallel test execution at the method, class, and suite levels.
Dependency Tests	Do not directly support dependency tests	Natively support dependency tests
Grouping Tests	Doesn’t allow the grouping of test cases	Allows grouping of test cases
Data-Driven Testing	Supports data-driven testing but does not have an in-built feature for the same	Supports data-driven testing using the DataProvider feature
Test Suite	JUnit uses @RunWith, and @Suite to run the test suite	TestNG uses an XML file to run the test suite
Reporting	Integrates with Maven to generate reports as it has no in-built HTML reporting	Has in-built HTML reports and it can also be integrated with Maven to generate extensive reports
Test Priority	Doesn’t allow test prioritization	Allows ordering and prioritizing test cases which ensure specific tests are executed before others
Test Execution	Its control over test execution is comparatively limited.	It allows better control over test execution through suite configuration, group execution, and parallelism settings

 

Let’s understand both frameworks in detail.

Understanding JUnit

JUnit is an open-source testing framework, and it is used to test small pieces of code, known as “units.” The idea is to test these small units of code before implementing them fully. This approach, called “testing first then coding,” improves productivity and makes the code more stable.

The latest version of JUnit is JUnit 5, and its current version is 5.7.1. While it was primarily built for unit testing, it can also be used for functional and integration testing with some adjustments and integrations.

One of the main advantages of JUnit is its support for Test Driven Development (TDD), where tests are written before writing the actual code. This helps ensure that the code is reliable and meets the required functionality.

JUnit is widely used in the testing community, especially for web automation testing when combined with the Selenium web driver. It provides a straightforward and elegant syntax through annotations, making it easy to understand and work with. Assertions in JUnit allow testers to check if the test results are as expected.

Features and Benefits of JUnit

• Fast Code Writing and Testing: JUnit is an open-source framework that enables developers to write and test code quickly, and improve code quality.
• Test Annotations: It provides several test annotations that help identify test methods, making it easier to organize and execute tests.

• Assertions for Expected Results: With JUnit, developers can use various assertions to test expected results, ensuring the code behaves as expected.
• Test Runners: It offers test runners to run tests smoothly and efficiently.
•  Automatic Test Execution: JUnit tests run automatically and provide immediate feedback, saving time and effort in the testing process.
• Debugging Support: It supports debugging, allowing developers to identify and fix issues in their scripts more quickly.
• Focus on Java 8 and Above: The latest version, JUnit 5, focuses on Java 8 and above, keeping up with the latest advancements in the language.
• Simplicity: It is straightforward and less complex, making it easy to use and understand.
• Test Suite Organization: It allows tests to be organized into test suites containing test cases and even other test suites, improving test management.
• Progress Visualization: JUnit shows test progress with a visual bar that turns green for smooth running tests and red when a test fails, providing clear feedback on test outcomes.

How to Install and Set Up JUnit?

JUnit requires Java version 8 and above so you can download Java from here.

You can add JUnit to your Java project using a build tool like Maven, or Gradle, or manually by downloading the JAR files.

You can download the JUnit jars from here.

• Using Maven

Add the below dependency to your project’s pom.xml file:

<dependency>

<groupId>org.junit.jupiter</groupId>

<artifactId>junit-jupiter</artifactId>

<version>5.7.1</version>

<scope>test</scope>

</dependency>

• Using Gradle

Add this to your build.gradle file:

testImplementation ‘org.junit.jupiter:junit-jupiter:5.7.1’

Once you add the above dependencies, all required jars will be installed:

junit-jupiter-api.jar

junit-jupiter-engine.jar

junit-platform-commons.jar

Junit-platform-engine.jar

This was the basic setup for JUnit 5.

JUnit Test Annotations

JUnit 5 uses annotations, which are like special tags represented by ‘@’, to provide extra information about the test methods and classes.

Here are some most commonly used annotations:

@Test: It indicates that a method is a test method.

@BeforeAll: Denotes the annotated method should run before all the tests in the class.

@AfterAll: Denotes the annotated method should run after all the tests in the class.

@BeforeEach: It marks a method to run before each individual test.

@AfterEach: It marks a method to run after each individual test.

@Tag: Used for declaring filtering tests or grouping tests either at the class or method level.

To know more annotations, click here.

Test Suites In JUnit

A test suite is basically putting multiple test cases together in a single package, allowing you to run them all at once.

To create a test suite in JUnit 5, you can use @RunWith and @Suite Classes.

Example: You have two test classes named ‘JUnitTestSuiteDemo1’ and ‘JUnitTestSuitDemo2’, and you want to create a test suite that includes both of them. The code to create the test suite would look like this:

@RunWith(Suite.class)

@Suite.SuiteClasses({

JUnitTestSuiteDemo1.class,

JUnitTestSuitDemo2.class

})

Writing JUnit Test Case

Here’s a simple JUnit test case example:

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

import example.util.Calculator;

import org.junit.jupiter.api.Test;

class MyFirstJUnitJupiterTests {

private final Calculator calculator = new Calculator();

@Test

void addition() {

assertEquals(2, calculator.add(1, 1));

}

}

JUnit Jupiter (JUnit 5) uses the @Test annotation from the ‘org.junit.jupiter.api’ package instead of ‘org.junit.Test’ used in JUnit 4 and earlier versions. Additionally, the assertions have been moved to the ‘org.junit.jupiter.api.Assertions’ class, and the test class doesn’t need to extend any specific class or implement any interface.

Understanding TestNG

TestNG is a Java-based test automation framework inspired by JUnit, but it goes beyond JUnit’s capabilities. It’s called “Next Generation” (NG) because it brings additional functionalities and makes testing more powerful and user-friendly.

This framework is designed to cover various types of testing, such as Unit testing, Functional testing, and Integration testing. It helps testers organize their test cases in a structured way, ensuring that scripts are easy to read and maintain.

Unlike JUnit, where you might need multiple jars for different features, TestNG conveniently includes all its features in one jar. The latest version of TestNG is 7.6.0.

Features and Benefits of TestNG

• Java Feature Support: TestNG leverages more Java features, making it powerful and flexible for testing Java applications.
• XML-Based Test Configurations: It supports XML-based test configurations, making it simple to manage and organize test suites.
• Parameterization of Test Methods: It enables parameterization of test methods, allowing testers to pass different values to the same test method for various scenarios.
• Multithreading Testing: TestNG supports multithreaded testing, allowing tests to run concurrently, reducing overall test execution time.
• Data-Based Testing: TestNG allows users to perform data-based testing using @DataProvider.
• HTML and XML Report Generation: Allows generating reports in HTML and XML formats, providing clear and detailed test execution results.
• Multiple Before and After Annotations: supports multiple Before and After test annotations, allowing testers to set up pre-test and post-test configurations easily.
• Open APIs for Developers: Offers open APIs accessible to developers, allowing them to extend and customize its functionalities.
• Ordering and Grouping of Tests: Supports the ordering and grouping of tests, providing flexibility in test execution.
• Dependency Testing: Allows testers to make tests dependent on each other using ‘dependsOnMethods’ and ‘dependsOnGroups’ attributes.
• How to Install and Set Up TestNG?
• Download and install Java from here.
• Download the TestNG jar file from here. This jar contains the TestNG libraries that your project will be using for testing.
• Open your project in your preferred development environment (like Eclipse) and add the TestNG jar file to your project’s build path.
• Add the given dependency to your project’s pom.xml file. This ensures that your Maven project includes the TestNG library when building and running tests.

<dependency>

<groupId>org.testng</groupId>

<artifactId>testng</artifactId>

<version>7.6.0</version> <!– Replace with the latest version –>

<scope>test</scope>

</dependency>

This was the basic setup for TestNG.

TestNG Test Annotations

Similar to JUnit, TestNG also used annotations, and here are some most commonly used:

@BeforeClass: This method runs before the first test method in the current class is executed.

@AfterClass: This method runs after all the test methods in the current class have been executed.

@BeforeMethod: This method runs before each test method.

@AfterMethod: This method runs after each test method.

@BeforeSuite: This method runs before all the methods in the test suites have run.

@AfterSuite: This method runs after all the methods in the test suites have run.

To know more annotations, click here.

Test Suites In TestNG

Test Suites in TestNG are defined in an XML file  (e.g. testng.xml).

Example:

<?xml version=”1.0″ encoding=”UTF-8″?>

<!DOCTYPE suite SYSTEM “http://testng.org/testng-1.0.dtd”>

<suite name=”DemoTestSuite”>

<test name=”DemoTest”>

<classes>

<class name=”demo.demo.TestSuiteDemo”/>

</classes>

</test>

</suite>

Writing TestNG Test Case

Here’s a simple TestNG test case example:

package example1;

import org.testng.annotations.*;

public class SimpleTest {

@BeforeClass

public void setUp() {

// code that will be invoked when this test is instantiated

@Test(groups = { “fast” })

public void aFastTest() {

System.out.println(“Fast test”);

@Test(groups = { “slow” })

public void aSlowTest() {

System.out.println(“Slow test”);  }

When you run this TestNG test case, TestNG will execute the test methods ‘aFastTest()’ and ‘aSlowTest()’ based on their group classification. The ‘setUp()’ method will be invoked once before any of the test methods are executed.

In addition to JUnit and TestNG, there are other testing tools and services available that can be used for Selenium automation testing. One notable tool is LambdaTest, which provides a cloud-based Selenium Grid infrastructure that can help you run your tests efficiently and scalably.

LambdaTest provides a cloud-based infrastructure allowing the testing community to effortlessly run tests across 3000+ test environments and real devices. The tool eliminates the need for setting up and managing your own Selenium Grid. With a cloud-based parallel execution, testers save a significant amount of test execution time that improves overall testing efficiency.

With seamless parallel testing, LambdaTest provides an extensive range of features that streamlines the test automation process. Features like screenshot capture, video recording, and bug reporting enable effective debugging and issue identification. By harnessing these capabilities, you can efficiently automate your testing and obtain valuable insights to ensure the quality and reliability of your applications.

Conclusion

JUnit and TestNG are two widely used Java frameworks for Selenium Automation Testing. JUnit provides a simple syntax, making it easy to understand and implement test cases. JUnit 4 had limitations in test case management, but JUnit 5 addressed those issues and introduced new features.

On the other hand, TestNG supports multiple Java features, multi-threaded testing, parameterization, and powerful grouping and dependency management.

For parallel testing in Selenium, TestNG gets an advantage, making it a preferred choice in this TestNG vs JUnit comparison.

Both JUnit and TestNG are highly capable for Selenium automation testing. While TestNG offers a few additional features compared to JUnit, the choice between the two depends on project requirements and flexibility.