How to get testcase data on method invocation in TestNG?

Question

I am using the IInvokedMethodListener in the TestNG package to listen for each method execution of my test case. In each method, I am trying to retrieve the data (test case data) for each case.

I have been searching around the API but am unable to find any useful methods. Has anyone tried something similar and is successful?

Answer 1

Here's how you do it.

A test class sample that feeds off of parameters from the suite xml.

import org.assertj.core.api.Assertions;
import org.testng.annotations.Parameters;
import org.testng.annotations.Test;

public class TestClassUsingParameters {

    @Parameters({"studentName", "studentAge"})
    @Test
    public void testMethod(String name, int age) {
        Assertions.assertThat(name).isNotEmpty();
        Assertions.assertThat(age).isGreaterThan(0);
    }
}

A test class sample that feeds off of parameters from a data provider.

import org.assertj.core.api.Assertions;
import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;

public class TestClassUsingDataProvider {
    @Test(dataProvider = "dp")
    public void testMethod(String name, int age) {
        Assertions.assertThat(name).isNotEmpty();
        Assertions.assertThat(age).isGreaterThan(0);
    }

    @DataProvider(name = "dp")
    public Object[][] getData() {
        return new Object[][]{
                {"Jack Daniels", 10},
                {"Napolean", 15}
        };
    }
}

Here's how the listener implementation would look like, which prints the parameters that are fed into the test method in either cases.

import org.testng.IInvokedMethod;
import org.testng.IInvokedMethodListener;
import org.testng.ITestResult;

import java.util.Arrays;

public class SampleListener implements IInvokedMethodListener {

    @Override
    public void beforeInvocation(IInvokedMethod method, ITestResult testResult) {
        Object[] parameters = testResult.getParameters();
        if (parameters != null) {
            printer("beforeInvocation", method, parameters);
        }
    }

    @Override
    public void afterInvocation(IInvokedMethod method, ITestResult testResult) {
        Object[] parameters = testResult.getParameters();
        if (parameters != null) {
            printer("afterInvocation", method, parameters);
        }
    }

    private void printer(String prefix, IInvokedMethod method, Object[] parameters) {
        String msg = String.format("Running %s() for method %s() with parameters: %s", prefix,
                method.getTestMethod().getMethodName(),
                Arrays.toString(parameters));
        System.err.println(msg);
    }
}

Finally here's how the suite xml looks like

<?xml version="1.0"?>
<!DOCTYPE suite SYSTEM "http://testng.org/testng-1.0.dtd">
<suite name="48697918_suite" verbose="2">
    <listeners>
        <listener class-name="com.rationaleemotions.stackoverflow.qn48697918.SampleListener"/>
    </listeners>
    <test name="48697918_test1">
        <classes>
            <class name="com.rationaleemotions.stackoverflow.qn48697918.TestClassUsingParameters">
                <parameter name="studentName" value="Jack Daniels"/>
                <parameter name="studentAge" value="15"/>
            </class>
            <class name="com.rationaleemotions.stackoverflow.qn48697918.TestClassUsingDataProvider"/>
        </classes>
    </test>
</suite>

Here's the output:

...
... TestNG 6.14.2 by Cédric Beust ([email protected])
...

Running beforeInvocation() for method testMethod() with parameters: [Jack Daniels, 15]

Running afterInvocation() for method testMethod() with parameters: [Jack Daniels, 15]
Running beforeInvocation() for method testMethod() with parameters: [Jack Daniels, 10]
Running afterInvocation() for method testMethod() with parameters: [Jack Daniels, 10]
Running beforeInvocation() for method testMethod() with parameters: [Napolean, 15]
Running afterInvocation() for method testMethod() with parameters: [Napolean, 15]
PASSED: testMethod("Jack Daniels", 15)
PASSED: testMethod("Jack Daniels", 10)
PASSED: testMethod("Napolean", 15)

===============================================
    48697918_test1
    Tests run: 3, Failures: 0, Skips: 0
===============================================

===============================================
48697918_suite
Total tests run: 3, Failures: 0, Skips: 0
===============================================