We are listing 50 testng interview questions and answers in this post. If any important question is missed from our side please add it in the comment. we will update our post accordingly What is TestNG? TestNG is a Java-based testing framework used for writing and executing test cases for a variety of applications, including those written in Java. It provides a flexible and powerful way to write tests, which can be organized into test suites, and can be run in parallel for improved performance. TestNG also provides a number of advanced features, such as data-driven testing, testing of parameters, and configuration through XML files. What are the advantages of using TestNG? Advantages of using TestNG: Easy to use: TestNG has a simple and user-friendly API that makes it easy to write tests. Supports multiple testing styles: TestNG supports a variety of testing styles including unit, functional, integration, and end-to-end testing. TestNG provides advanced test configuration: It supports flexible test configuration options, including test groups, parameters, and data-driven testing. Integration with CI/CD tools: TestNG integrates easily with popular CI/CD tools such as Jenkins and Maven, making it easy to automate testing and report results. Supports parallel testing: TestNG provides support for parallel testing, allowing tests to run simultaneously and reducing the total test execution time. TestNG provides detailed test reports: It generates detailed test reports that provide insights into test execution, including test execution times, results, and stack traces. Flexible test execution order: TestNG allows users to specify the order in which tests should be executed, making it possible to run dependent tests in a specific order. What is the difference between TestNG and JUnit? TestNG and JUnit are two popular Java testing frameworks. They are used for testing Java applications and are both open-source. Here are some differences between the two: Annotation: TestNG uses more advanced annotations such as @DataProvider, @Factory, and @Listeners which make it easier to manage test cases. JUnit, on the other hand, only has basic annotations like @Test, @Before, and @After. Test Configuration: TestNG has a better way of configuring tests, with XML configuration files, while JUnit relies on annotations and hard-coded parameters. Test Prioritization: TestNG allows you to prioritize your tests so that they run in a specific order. JUnit does not have this feature. Test Grouping: TestNG supports test grouping and enables you to run tests based on groups. JUnit does not support this feature. Test Reports: TestNG generates more comprehensive and detailed reports than JUnit. Test Suites: TestNG provides more control over test suites, allowing you to run multiple tests in a single test suite. JUnit does not have this feature. In conclusion, TestNG offers more advanced features and greater control over your tests compared to JUnit, making it the preferred choice for large-scale applications. Can you explain the basic structure of a TestNG test case? TestNG test cases have the following basic structure: Annotation: The first line of a TestNG test case is an annotation that defines the method as a test case. The most commonly used annotation is @Test. Method signature: The method signature defines the name of the test case, any parameters it requires, and its return type. Setup: This section of the test case sets up any necessary resources, such as test data, before the test case is run. Execution: The execution section is where the actual testing is performed. It is the core of the test case and where the logic and assertions are placed to determine if the test case has passed or failed. Tear down: This section of the test case cleans up any resources used during the test case execution. Assertions: Assertions are statements that are used to validate the expected outcome of the test case. If an assertion fails, the test case will be marked as failed. Example: How do you configure TestNG? To configure TestNG, follow these steps: Download and Install TestNG: To get started with TestNG, you first need to download and install it. You can download the latest version of TestNG from the official website (http://testng.org/doc/download.html). Set up TestNG in Eclipse: To set up TestNG in Eclipse, you need to install the TestNG plugin. Go to the Help menu in Eclipse, select Install New Software, and then add the TestNG update site. Create a TestNG Project: To create a TestNG project, go to the File menu in Eclipse, select New, and then select Project. Select TestNG in the left-hand menu, and then click Next. Write your Test Cases: Once you have created your TestNG project, you can start writing your test cases. To do this, you will need to create a Java class and annotate it with the @Test annotation. Run your Test Cases: To run your test cases, right-click on the class file that contains your test cases and select Run As > TestNG Test. Configure TestNG XML file: TestNG provides a powerful way to organize and run your test cases using an XML file. To create a TestNG XML file, you need to right-click on the project and select New > TestNG XML File. Run your TestNG XML file: To run your TestNG XML file, right-click on the XML file and select Run As > TestNG Suite. By following these steps, you can easily configure TestNG and start writing and running your test cases. How does TestNG support data-driven testing? TestNG supports data-driven testing through the use of data providers. Data providers are methods that return data in the form of arrays or collections, which can then be used to feed test cases. In TestNG, you can define data providers with the @DataProvider annotation, which specifies the data source for the test case. The data provider method is then called before the test case, passing the data to the test case as arguments. For example, suppose you have a test case that tests a login functionality. You can define a data provider that returns an array of username and password combinations, and then use this data to
