TestNG vs WebdriverIO comparison of testing frameworks
What are the differences between TestNG and WebdriverIO?

	TestNG https://testng.org/doc/documentation-main.html	WebdriverIO https://webdriver.io/
Programming language	Java	JavaScript
Category	Unit Testing, Intergration Testing, End-to-End Testing	Browser Automation, Unit Testing, Functional Testing
General info	TestNG is a testing framework for the Java programming language inspired by JUnit and NUnit TestNG is similar to JUnit and NUnit but with newer functionalities such as: annotations, test that your code is multithread safe, flexible test configuration, support for data-driven testing (with @DataProvider), support for parameters, powerful execution model (no more TestSuite) and more... It's also designed to cover all categories of tests unit, functional, end-to-end, intergration... etc	WebdriverIO is the next-gen WebDriver test framework for Node.js made upon Selenium WebdriverIO is written in JavaScript and uses Selenium under the hood. It also comes with its own inbuilt test runner and supports other testing frameworks like Jasmine, Cucumber, and Mocha
xUnit Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.	No	Yes
Client-side Allows testing code execution on the client, such as a web browser	Yes The scope of testing with testNg is wide and you can test various front-end functionalities and behaviours with it	Yes WebdriverIO allows the use of advanced CSS selectors and makes it easy to find elements for front-end testing
Server-side Allows testing the bahovior of a server-side code	Yes You can test server-side functionalities and behaviours with TestNg	Yes It can be used to test server side behaviour and functionality
Fixtures Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test	Yes Fixtures are inbuilt into testNG, these are the annotations which are: @BeforeSuite, @AfterSuite, @BeforeTest, @AfterTest, @BeforeGroups, @AfterGroups, @BeforeClass, @AfterClass, @BeforeMethod, @AfterMethod	Yes WebdriverIO supports the creation of fixtures
Group fixtures Allows defining a fixed, specific states of data for a group of tests (group-fixtures). This ensures specific environment for a given group of tests.	Yes You can use various fixtures to setup environments for group tests	Yes WebdriverIO supports the creation of group fixtures
Generators Supports data generators for tests. Data generators generate input data for test. The test is then run for each input data produced in this way.	N/A	N/A
Licence Licence type governing the use and redistribution of the software	Apache License 2.0	MIT License
Mocks Mocks are objects that simulate the behavior of real objects. Using mocks allows testing some part of the code in isolation (with other parts mocked when needed)	Yes By Use of an external library like mockit which intergrates well with testNG	Yes It contains a mocking service called 'wdio-wiremock-service'
Grouping Allows organizing tests in groups	Yes Multiple test cases can be grouped more easily by converting them into testng.xml file, in which you can make priorities which test case should be executed first	Yes WebdriverIO allows one to build test suites, you can run these test in parallel and organize them by adjusting the 'maxInstances' property in your config file
Other Other useful information about the testing framework