TestNG | Modify testng.xml file programmatically

At times, we may need to modify testng.xml programmatically before the test suite execution starts, for example by adding a listener in the background or exclude a test case with certain group tag.

TestNG provides the IAlterSuiteListener interface to implement a hook to capture the testng.xml instance before the test suite executes. When we get the XmlSuite instance, we can add or remove attributes as needed.

public class TestNGListener implements IAlterSuiteListener {
    
    @Override
    public void alter(List<XmlSuite> suites) {
        for(XmlSuite suite:suites) {
            suite.addIncludedGroup("bdd_runner");
      }
   }
}