TestNG vs JUnit: Java Testing Frameworks Comparison 2026

TL;DR

• JUnit 5: Modern, extensible, standard for unit testing, Spring integration
• TestNG: Feature-rich, parallel execution, data providers, Selenium-friendly
• For unit tests: JUnit 5 (industry standard, better IDE support)
• For Selenium/E2E: TestNG (groups, parallel, reporting) or JUnit 5 (modern)
• Migration: JUnit 5 and TestNG now have similar features

Reading time: 9 minutes

JUnit and TestNG are the dominant Java testing frameworks. JUnit is the standard for unit testing, TestNG emerged to add features JUnit lacked. JUnit 5 has narrowed the gap significantly.

Quick Comparison

Annotation Comparison

Test Lifecycle

TestNG has more granular lifecycle annotations.

Test Examples

JUnit 5 Test

import org.junit.jupiter.api.*;
import static org.junit.jupiter.api.Assertions.*;

@DisplayName("Calculator Tests")
class CalculatorTest {

    private Calculator calc;

    @BeforeEach
    void setUp() {
        calc = new Calculator();
    }

    @Test
    @DisplayName("Addition works correctly")
    void testAddition() {
        assertEquals(5, calc.add(2, 3));
    }

    @Test
    @Tag("slow")
    void testComplexOperation() {
        // Tagged for selective execution
        assertNotNull(calc.complexCalc());
    }
}

TestNG Test

import org.testng.annotations.*;
import static org.testng.Assert.*;

public class CalculatorTest {

    private Calculator calc;

    @BeforeMethod
    public void setUp() {
        calc = new Calculator();
    }

    @Test(description = "Addition works correctly")
    public void testAddition() {
        assertEquals(calc.add(2, 3), 5);
    }

    @Test(groups = {"slow"})
    public void testComplexOperation() {
        // Grouped for selective execution
        assertNotNull(calc.complexCalc());
    }
}

Data-Driven Testing

JUnit 5 Parameterized Tests

@ParameterizedTest
@CsvSource({
    "2, 3, 5",
    "0, 0, 0",
    "-1, 1, 0"
})
void testAddition(int a, int b, int expected) {
    assertEquals(expected, calc.add(a, b));
}

@ParameterizedTest
@MethodSource("provideNumbers")
void testWithMethodSource(int a, int b, int expected) {
    assertEquals(expected, calc.add(a, b));
}

static Stream<Arguments> provideNumbers() {
    return Stream.of(
        Arguments.of(2, 3, 5),
        Arguments.of(0, 0, 0)
    );
}

TestNG DataProvider

@DataProvider(name = "additionData")
public Object[][] provideData() {
    return new Object[][] {
        {2, 3, 5},
        {0, 0, 0},
        {-1, 1, 0}
    };
}

@Test(dataProvider = "additionData")
public void testAddition(int a, int b, int expected) {
    assertEquals(calc.add(a, b), expected);
}

TestNG’s DataProvider is more straightforward for complex data.

Parallel Execution

JUnit 5 Parallel

# junit-platform.properties
junit.jupiter.execution.parallel.enabled = true
junit.jupiter.execution.parallel.mode.default = concurrent
junit.jupiter.execution.parallel.config.strategy = fixed
junit.jupiter.execution.parallel.config.fixed.parallelism = 4

TestNG Parallel

<!-- testng.xml -->
<suite name="Parallel Suite" parallel="methods" thread-count="4">
    <test name="Tests">
        <classes>
            <class name="com.example.CalculatorTest"/>
        </classes>
    </test>
</suite>

TestNG’s XML configuration offers more control over parallel execution.

Test Dependencies

JUnit 5 Ordering

@TestMethodOrder(MethodOrderer.OrderAnnotation.class)
class OrderedTest {

    @Test
    @Order(1)
    void createUser() { }

    @Test
    @Order(2)
    void verifyUser() { }
}

TestNG Dependencies

@Test
public void createUser() { }

@Test(dependsOnMethods = {"createUser"})
public void verifyUser() { }

@Test(dependsOnGroups = {"setup"})
public void runAfterSetup() { }

TestNG has explicit method dependencies; JUnit uses ordering.

When to Choose JUnit 5

1. Unit testing — industry standard for Java unit tests
2. Spring projects — excellent Spring Boot integration
3. IDE support — better tooling in IntelliJ and Eclipse
4. Modern Java — designed for Java 8+ with lambdas
5. Simple projects — less configuration needed

When to Choose TestNG

1. Selenium testing — established in browser automation
2. Complex test suites — XML configuration, groups
3. Enterprise testing — extensive reporting, listeners
4. Parallel execution — more granular control
5. Legacy projects — existing TestNG infrastructure

AI-Assisted Testing

Both frameworks benefit from AI tools.

What AI helps with:

• Generating test cases from code
• Creating data providers
• Writing assertions
• Converting between frameworks

What needs humans:

• Test strategy design
• Edge case identification
• Integration test planning

Migration Between Frameworks

TestNG to JUnit 5

Note: Assertion parameter order differs.

JUnit 5 to TestNG

Reverse the table above. Consider:

• TestNG needs testng.xml for advanced features
• Groups offer more flexibility than tags

FAQ

Is TestNG better than JUnit?

TestNG offers more built-in features like parallel execution, data providers, flexible grouping, and rich reporting. JUnit 5 has significantly caught up with parameterized tests, parallel execution, and tags. Choose TestNG for complex test automation and Selenium projects, JUnit 5 for standard unit testing and Spring applications.

Should I use TestNG or JUnit for Selenium?

TestNG is traditionally preferred for Selenium due to parallel browser execution, test grouping, method dependencies, and built-in reporting. However, JUnit 5 now supports these features adequately. Both work equally well with Selenium WebDriver. Choose based on team expertise and existing infrastructure.

Can I use TestNG and JUnit together?

Technically yes, but not recommended in the same module. Some projects use JUnit for unit tests and TestNG for integration/Selenium tests in separate modules. This adds complexity. Most teams choose one framework for consistency and simpler build configuration.

Which is more popular?

JUnit has larger overall adoption, especially for unit testing. TestNG is popular in enterprise QA and Selenium automation. Both are actively maintained with strong communities. JUnit 5’s modern features have attracted many TestNG users, while TestNG retains loyalty in automation testing.

See Also

• JUnit Tutorial - Complete JUnit 5 guide
• TestNG Tutorial - Comprehensive TestNG guide
• Selenium Tutorial - WebDriver basics
• Java Testing Best Practices - Testing strategies