What is TestNG? And whats the difference between Junit and TestNG

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

• Annotations.
• Flexible test configuration.
• Support for data-driven testing (with @DataProvider).
• Support for parameters.
• Allows distribution of tests on slave machines.
• Powerful execution model (no more TestSuite).
• Supported by a variety of tools and plug-ins (Eclipse, IDEA, Maven, etc...).
• Dependent methods for application server testing.

If you want to learn TestNG you can download it and see its documentation at “http://testng.org/doc/index.html”.

TestNG is extensively used in Selenium automation and Code testing instead of Junit due to its advantages over it.

Using TestNG Selenium automation becomes simplified and also the Parallel execution using Selenium Grid becomes easy.

TestNG have a lot of features in it and hence I wont be covering every thing in my blog. But will only talk about advantages of TestNG over Junit. I will be discussing about different ways of using TestNg functions in my coming blogs.

Advantages of TestNG over Junit

1. In Junit we have to declare @BeforeClass and @AfterClass which is a constraint where as in TestNG there is no constraint like this.
2. Additional Levels of setUp/tearDown level are available in TestNG like @Before/AfterSuite,@Before/AfterTest and @Before/AfterGroup
3. No Need to extend any class in TestNG.
4. There is no method name constraint in TestNG as in Junit. You can give any name to the test methods in TestNG
5. In TestNG we can tell the test that one method is dependent on another method where as in Junit this is not possible. In Junit each test is independent of another test.
6. Grouping of testcases is available in TestNG where as the same is not available in Junit.
7. Execution can be done based on Groups. For ex. If you have defined many cases and segregated them by defining 2 groups as Sanity and Regression. Then if you only want to execute the “Sanity” cases then just tell TestNG to execute the “Sanity” and TestNG will automatically execute the cases belonging to the “Sanity” group.
8. Also using TestNG your selenium testcase execution can be done in parallel.