Annotation Transformers

TestNG allows you to modify the content of all the annotations at runtime.

This is especially useful if the annotations in the source code are right most of the time, but there are a few situations where you’d like to override their value.

In order to achieve this, you can build a class that implements IAnnotationTransformer

This is a special TestNG listener. It can be added into TestNG via the following mechanisms.

Via xml suite file

You can use the <listeners> tag to specify an implementation of IAnnotationTransformer in your suite xml file.

Via command line arguments

You can use the command line argument -listener to specify the fully qualified class name of the implementation of IAnnotationTransformer as shown below.

java org.testng.TestNG -listener MyTransformer testng.xml

Via your code

An implementation of IAnnotationTransformer can be wired in via your code as well (In case you are working with using the TestNG APIs for programmatically running your tests.)

TestNG tng = new TestNG();
tng.addListener(new MyTransformer());
// ...
Please don’t use the @Listeners annotation to wire-in an implementation of org.testng.IAnnotationTransformer. Doing so will cause your implementation to be ignored. This is because TestNG needs to be able to parse all annotations before starting to execute them and @Listeners is also one such annotation.

The annotation transformer allows you to alter the below types of annotations at runtime:

  • @Test annotation on test methods.

  • Any of the common attributes associated with the below listed configuration annotations:

    • @BeforeSuite

    • @AfterSuite

    • @BeforeTest

    • @AfterTest

    • @BeforeClass

    • @AfterClass

    • @BeforeMethod

    • @AfterMethod

  • @Listeners annotation on test classes.

  • @Factory annotation used to mark constructors or a factory method as test factories.

  • @DataProvider annotated data providers.

When the method transform() is invoked, you can call any of the setters on the ITestAnnotation test parameter to alter its value before TestNG proceeds further.

For example, here is how you would override the attribute invocationCount but only on the test method invoke() of one of your test classes:

public class MyTransformer implements IAnnotationTransformer {
  public void transform(ITestAnnotation annotation, Class testClass, Constructor testConstructor, Method testMethod) {
    if ("invoke".equals(testMethod.getName())) {