TestNG vs. JUnit: Which Testing Framework Is Best?

The widely used tools or frameworks for unit testing are JUnit and TestNG.

Here are some pointers as to why and how these are the most used unit QA/Testing frameworks:

1. Both TestNG and JUnit are open Sources.
2. Both TestNG and JUnit are Testing frameworks used for Unit Testing.
3. TestNG is inspired by JUnit, so in a way these are similar.
4. Few more functionalities are added to TestNG which makes it more powerful than JUnit.
5. Both JUnit and TestNG are without a doubt the most popular testing frameworks out there. In fact, when we looked into The Top 100 Java Libraries used in 2016, both of them made the top-20.
6. JUnit is ranked first with a presence in 62% of the projects, and TestNG was in at #20 with 6%.

Before you start working with JUnit or TestNG, you should have a basic knowledge of Unit Testing and Quality Assurance (QA).

Unit Testing

Unit Testing is a level of software testing where individual units of software are tested. A unit is the smallest testable part of the software where usually few inputs are provided to test or verify a single functionality of a software system. Unit testing confirms that whether the project is developing in the right direction or not.

The process of testing begins with Unit testing where an initially developed software is tested. Unit testing is the first level of the testing which is performed prior to the Integration testing or System testing.

Tools or framework available to perform unit testing:-

• JUnit
• NUnit
• SimpleTest
• Unity Test tool
• TestNG

What is JUnit?

JUnit is an open-source Unit Testing framework. JUnit is a Java library for testing source code. JUnit is initially developed by Erich Gamma and Kent Beck. It is an instance of xUnit architecture. As the name implies, it is used for Unit Testing of a small chunk of code.

What is TestNG?

TestNG is a testing framework that is inspired by JUnit and NUnit; however, TestNG introduces some new functionality that makes it more powerful and easier to use. TestNG is designed to cover all categories of tests: unit, functional, end-to-end, integration, etc., and it requires JDK 5 or higher.

TestNG is a testing framework inspired from JUnit and NUnit, but introducing some new functionalities that make it more powerful and easier to use.

TestNG is an automated testing framework, where NG means Next Generation. TestNG is similar to JUnit but it is not a JUnit extension. TestNG is inspired by JUnit and is designed to be better than JUnit, especially when testing integrated classes.

The creator of TestNG is Cedric Beust.

JUnit vs. TestNG:-

1) Annotations

Both JUnit and TestNG works using annotations and most of the annotation look similar. Like @Before annotation in JUnit is similar to @BeforeMethod annotation in TestNG and @ignore annotation in JUnit is similar to @Test(enable=false) in TestNG.

Below mentioned all the annotations used by JUnit and TestNG:-

2) Test suite

The “Test Suite” means bundle a few unit tests and run it together. Test Suite refers to the integration of multiple unit tests together and executing them in parallel. This feature is implemented in both JUnit 4 and TestNG. However, both are using different methods to implement it.

JUnit:-

The “@RunWith” and “@Suite” are used to run the suite test. The below class means both unit test “JunitTest1” and “JunitTest2” run together after JunitTest5 executed

@RunWith(Suite.class)

@Suite.SuiteClasses({

JunitTest1.class,

JunitTest2.class

})

public class JunitTest5 {

}

TestNG:-

An XML file is used to run the suite test. The below XML file means both unit test “TestNGTest1” and “TestNGTest2” will run it together.

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

<suite name=”My test suite”>

<test name=”testing”>

<classes>

<class name=”com.fsecure.demo.testng.TestNGTest1″ />

<class name=”com.fsecure.demo.testng.TestNGTest2″ />

</classes>

</test>

</suite>

3) Ignore Test

@ignore annotation is used to skip a test while working with JUnit4

@Test(enabled=false) annotation is used to skip a test while working with TestNG

4) Exception Test

Exception testing is available both in TestNG and JUnit4. It is used to check, which exception is thrown from the test?

5) Timeout

This feature is implemented both in TestNG and JUnit4.Timeout is used to terminate a test that takes longer than a specified time (in milliseconds).

6)  Group Test

Group test is a new innovative feature in TestNG, which doesn’t exist in the JUnit framework. It permits you to dispatch methods into proper portions and perform sophisticated groupings of test methods.

Group tests provide maximum flexibility in how you partition your tests and don’t require you to recompile anything if you want to run two different sets of tests back to back.

Groups are specified in your testng.xml file using the <groups> tag. It can be found either under the <test> or <suite> tag. Groups specified in the <suite> tag apply to all the <test> tags underneath.

7) Reporting 

Reporting is the most important part of any test execution, as it helps the user understand the result of the test execution, point of failure, and the reasons for failure. Logging, on the other hand, is important to keep an eye on the execution flow or for debugging in case of any failures.

TestNG, by default, generates a different type of report for its test execution. This includes an HTML and an XML report output. TestNG also allows its users to write their own reporters and use them with TestNG. There is also an option to write your own loggers, which are notified at runtime by TestNG.

I hope you found this article useful. For more information on Software Development or QA Testing, you can contact us at Digital Agency in Philadelphia.