How to get the exception that was thrown when a Cucumber test failed in Java?

Question

I can perform actions on test failure by using:

@After
public void afterTest(Scenario scenario) {
    if (scenario.isFailed()) {
        /*Do stuff*/
    }
}         


        

Answer 1

After a lot of experimentation I now removed the Before/After-Annotations and rely on Cucumber-Events instead. They contain the TestCase (which is what the Scenario-class wraps) and a Result where you can call getError(); to get the Throwable.

Here is a simple example to get it working

import io.cucumber.plugin.EventListener;
import io.cucumber.plugin.event.EventPublisher;
import io.cucumber.plugin.event.Result;
import io.cucumber.plugin.event.Status;
import io.cucumber.plugin.event.TestCase;
import io.cucumber.plugin.event.TestCaseFinished;
import io.cucumber.plugin.event.TestCaseStarted;
import org.openqa.selenium.WebDriver;

public class TestCaseListener implements EventListener {
    @Override
    public void setEventPublisher(final EventPublisher publisher) {
        publisher.registerHandlerFor(TestCaseStarted.class, this::onTestCaseStarted);
        publisher.registerHandlerFor(TestCaseFinished.class, this::onTestCaseFinished);
    }

    public void onTestCaseStarted(TestCaseStarted event) {
        TestCase testCase = event.getTestCase();
        System.out.println("Starting " + testCase.getName());

        // Other stuff you did in your @Before-Method.
        // ...
    }

    private void onTestCaseFinished(final TestCaseFinished event) {
        TestCase testCase = event.getTestCase();
        System.out.println("Finished " + testCase.getName());

        Result result = event.getResult();
        if (result.getStatus() == Status.FAILED) {
            final Throwable error = result.getError();
            error.printStackTrace();
        }

        // Other stuff you did in your @After-Method.
        // ...
    }
}

All that's left to do is to register this class as a Cucumber-Plugin. I did this by modifying my @CucumberOptions-annotation:

@CucumberOptions(plugin = {"com.example.TestCaseListener"})

I find this much cleaner than all of this reflection-madness, however it requires a lot more code-changes.

Edit

I don't know why, but this caused a lot of tests to randomly fail in a multithreaded environment. I tried to figure it out, but now also use the ugly reflections mentioned in this thread:

public class SeleniumUtils {
private static final Logger log = LoggerFactory.getLogger(SeleniumUtils.class);

private static final Field field = FieldUtils.getField(Scenario.class, "delegate", true);
private static Method getError;

public static Throwable getError(Scenario scenario) {
    try {
        final TestCaseState testCase = (TestCaseState) field.get(scenario);
        if (getError == null) {
            getError = MethodUtils.getMatchingMethod(testCase.getClass(), "getError");
            getError.setAccessible(true);
        }
        return (Throwable) getError.invoke(testCase);
    } catch (Exception e) {
        log.warn("error receiving exception", e);
    }
    return null;
}
}