TestNG Listeners in Selenium:

• The listener is defined as the interface which modifies the behavior of the default TestNG.

• As the name suggests, listeners “listen” for the event defined in the Selenium script and behave accordingly.

• It is used in selenium by applying listeners interface.

• TestNG listeners use to create logs in Selenium.

• TestNG can generate step by step logs with the help of Listeners.

• It allows customizing TestNG reports or logs with the help of listeners.

TestNG provides us below listeners:

1. IExecutionListener
2. IAnnotationTransformer
3. ISuiteListener
4. ITestListener
5. IConfigurationListener
6. IMethodInterceptor
7. IInvokedMethodListener
8. IHookable
9. IReporter

Note: These interfaces are used in selenium to generate logs or customize the testing reports with the help of Step by Step Scenario’s.

ITestListener ( I ):

When  we use ITestListener:

• After successfully completing each test.

• After each failed test.

• After each test skipped.

• After the completion of all tests.

Methods in ITestListener are following below:

 1. OnStart( ):

onStart method is called when any Test starts.

2. onTestSuccess( ):

onTestSuccess method is called on the success of any Test.

3. onTestFailure( ):

onTestFailure method is called on the failure of any Test.

4. onTestSkipped( ):

onTestSkipped method is called on skipped of any Test.

5. onTestFailedButWithinSuccessPercentage( ):

method is called each time Test fails but is within success percentage.

6. onFinish( ):

onFinish method is called after all Tests are executed.

Step 1: Create a simple class and implement ITestListener listener.

Step 2: Add all unimplemented methods.

Note: Before execute program add Listener class into TestNG.xml file then Run as TestNG Suite to TestNG listeners in Selenium.

Output:

Step 3:  Add listener class into TestNG.xml file.

Example: Add listeners into existing TestNG.xml file.