How to use Junit Listener

JUnit Listeners

If you want to do some operations when your tests are started, passed, finished, failed, or skipped/ignored, you can use Listeners. Both JUnit and TestNG provide us Listeners, and in this article, I will explain how to add JUnit Listeners in your automation framework.

Listeners listen and handle events while your automation code is running. We can add a listener by creating a custom Runner. Then, we can use this custom runner in our test class with @RunWith annotation.

First, let’s write our Listener class by extending JUnit’s RunListener class and overriding its methods. I called our listener class as MyExecutionListener.

MyExecutionListener.java

MyExecutionListener

 

 

package junitexamples.listener;
 
/**
 * Created by ONUR BASKIRT on 27.03.2016.
 */
 
import org.junit.Ignore;
import org.junit.runner.Description;
import org.junit.runner.Result;
import org.junit.runner.notification.Failure;
import org.junit.runner.notification.RunListener;
 
import java.util.Date;
 
public class MyExecutionListener extends RunListener {
 
    //Start and End time of the tests
    long startTime;
    long endTime;
 
    @Override
    public void testRunStarted(Description description) throws Exception {
        //Start time of the tests
        startTime = new Date().getTime();
        //Print the number of tests before the all tests execution.
        System.out.println("Tests started! Number of Test case: " + description.testCount() + "\n");
    }
 
    @Override
    public void testRunFinished(Result result) throws Exception {
        //End time of the tests
        endTime = new Date().getTime();
        //Print the below lines when all tests are finished.
        System.out.println("Tests finished! Number of test case: " + result.getRunCount());
        long elapsedSeconds = (endTime-startTime)/1000;
        System.out.println("Elapsed time of tests execution: " + elapsedSeconds +" seconds");
    }
 
    @Override
    public void testStarted(Description description) throws Exception {
        //Write the test name when it is started.
        System.out.println(description.getMethodName() + " test is starting...");
    }
 
    @Override
    public void testFinished(Description description) throws Exception {
        //Write the test name when it is finished.
        System.out.println(description.getMethodName() + " test is finished...\n");
    }
 
    @Override
    public void testFailure(Failure failure) throws Exception {
        //Write the test name when it is failed.
        System.out.println(failure.getDescription().getMethodName() + " test FAILED!!!");
    }
 
    //O.B: IntelliJ ignored by default. I did not succeed to run this method.
    //If you know any way to accomplish this, please write a comment.
    @Override
    public void testIgnored(Description description) throws Exception {
        super.testIgnored(description);
        Ignore ignore = description.getAnnotation(Ignore.class);
        String ignoreMessage = String.format(
                "@Ignore test method '%s()': '%s'",
                description.getMethodName(), ignore.value());
        System.out.println(ignoreMessage + "\n");
    }
}

 

 

Java

 

 

Second, we need to add the listener to the test execution. We can add the listener by calling the RunNotifier.addListener() method. This will register our JUnit Listener. I faced with a problem when I tried to use RunListener class’s testRunStarted method. Then, I found a solution that triggers this method after registering the listener in the run method. I wrote a comment about this solution in below code.

 

MyTestRunner.java

MyTestRunner

package junitexamples.listener;
 
/**
 * Created by ONUR BASKIRT on 27.03.2016.
 */
 
import org.junit.AssumptionViolatedException;
import org.junit.internal.runners.model.EachTestNotifier;
import org.junit.runner.notification.RunNotifier;
import org.junit.runner.notification.StoppedByUserException;
import org.junit.runners.BlockJUnit4ClassRunner;
import org.junit.runners.model.InitializationError;
import org.junit.runners.model.Statement;
 
public class MyTestRunner extends BlockJUnit4ClassRunner {
 
    public MyTestRunner(Class<?> klass) throws InitializationError {
        super(klass);
    }
 
    @Override
    public void run (RunNotifier notifier){
        System.out.println("Executing run()");
        //Add Listener. This will register our JUnit Listener.
        notifier.addListener(new MyExecutionListener());
 
        //Get each test notifier
        EachTestNotifier testNotifier = new EachTestNotifier(notifier,
                getDescription());
        try {
            //In order capture testRunStarted method
            //at the very beginning of the test run, we will add below code.
            //Invoke here the run testRunStarted() method
            notifier.fireTestRunStarted(getDescription());
            Statement statement = classBlock(notifier);
            statement.evaluate();
        } catch (AssumptionViolatedException e) {
            testNotifier.fireTestIgnored();
        } catch (StoppedByUserException e) {
            throw e;
        } catch (Throwable e) {
            testNotifier.addFailure(e);
        }
    }
}

 

 

 

 

 

Java

 

 

Third, we need to write a test to verify our listener’s functionality. We register our custom runner with @RunWith(MyTestRunner.class) annotation and for alphabetic test execution, we add @FixMethodOrder(MethodSorters.NAME_ASCENDING) annotation.

 

Extra: Also, you can combine listeners with custom Retry Rule which described in other JUnit article. Thus, when your test fails, it will rerun the failed test according to given retry count.

ListenerExampleTest.java

ListenerExampleTest

 

package junitexamples.listener;
 
import jdk.nashorn.internal.ir.annotations.Ignore;
import org.junit.BeforeClass;
import org.junit.FixMethodOrder;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.MethodSorters;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.htmlunit.HtmlUnitDriver;
 
import static org.hamcrest.CoreMatchers.is;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.junit.Assert.assertEquals;
 
/**
 * Created by ONUR on 27.03.2016.
 */
@RunWith(MyTestRunner.class)
@FixMethodOrder(MethodSorters.NAME_ASCENDING)
public class ListenerExampleTest {
 
    static WebDriver driver;
    final private static String URL = "http://www.swtestacademy.com";
 
    @BeforeClass
    public static void setupTest(){
        driver = new HtmlUnitDriver();
        driver.get(URL);
    }
 
    /*
    //If you want, you can add Retry Rule. (I explained it in another post.)
    //Thus, when your test fails, it will rerun by given retry count.
    @Rule
    public RetryRule retryRule = new RetryRule(3);
    */
 
    @Test
    public void T01_PassTest() {
        //Check title
        assertThat(driver.getTitle(), is("Software Test Academy"));
    }
 
    @Test
    public void T02_FailTest() {
        //Check title
        assertEquals("Title is wrong!!!", "WRONG TITLE", driver.getTitle());
    }
 
    //IntelliJ ignored by default
    @Ignore
    public void T03_IgnoreTest() {
        //Check title is correct
        assertThat(driver.getTitle(), is("Software Test Academy"));
    }
 
    //Throw Exception
    @Test
    public void T04_ExceptionTest() {
        throw new RuntimeException();
    }
}

 

 

 

 

 

Java

 

Result: