TestNG vs JUnit 5: Complete Comparison for Java Testers

Introduction

Choosing between TestNG and JUnit 5 (Jupiter) is one of the most critical decisions for Java test automation teams. Both frameworks have evolved significantly, with JUnit (as discussed in Allure Framework: Creating Beautiful Test Reports) 5 introducing many features that were previously exclusive to TestNG. This comprehensive comparison will help you make an informed decision based on features, use cases, and migration strategies.

Historical Context

JUnit Evolution

JUnit 4 (2006): Introduced annotations, bringing Java testing into the modern era
JUnit 5 (2017): Complete rewrite with modular architecture (Platform, Jupiter, Vintage)

TestNG Origins

Created in 2004 by Cédric Beust, inspired by JUnit and NUnit
Design goal: Address JUnit’s limitations, particularly for integration and functional testing

Architecture Comparison

JUnit 5 Modular Architecture

JUnit 5 consists of three modules:

<!-- JUnit (as discussed in [REST Assured: Java-Based API Testing Framework for Modern Applications](/blog/rest-assured-api-testing)) Platform: Foundation for launching testing frameworks -->
<dependency>
    <groupId>org.junit.platform</groupId>
    <artifactId>junit (as discussed in [WebdriverIO: Extensibility, Multiremote, and Migration Guide](/blog/webdriverio-extensibility-multiremote-migration))-platform-launcher</artifactId>
</dependency>

<!-- JUnit Jupiter: New programming model and extension model -->
<dependency>
    <groupId>org.junit.jupiter</groupId>
    <artifactId>junit-jupiter-engine</artifactId>
    <version>5.10.1</version>
</dependency>

<!-- JUnit Vintage: Support for JUnit 3 and JUnit 4 tests -->
<dependency>
    <groupId>org.junit.vintage</groupId>
    <artifactId>junit-vintage-engine</artifactId>
    <version>5.10.1</version>
</dependency>

TestNG Single Module

<dependency>
    <groupId>org.testng</groupId>
    <artifactId>testng</artifactId>
    <version>7.8.0</version>
</dependency>

Annotations Comparison

Feature	TestNG	JUnit 5	Notes
Before all tests in class	`@BeforeClass`	`@BeforeAll`	JUnit 5 requires static method
After all tests in class	`@AfterClass`	`@AfterAll`	JUnit 5 requires static method
Before each test	`@BeforeMethod`	`@BeforeEach`	Similar functionality
After each test	`@AfterMethod`	`@AfterEach`	Similar functionality
Suite setup	`@BeforeSuite`	N/A	TestNG advantage
Suite teardown	`@AfterSuite`	N/A	TestNG advantage
Test groups	`@Test(groups)`	`@Tag`	Different approach
Ignore test	`@Test(enabled=false)`	`@Disabled`	JUnit 5 more explicit
Expected exception	`@Test(expectedExceptions)`	`assertThrows()`	JUnit 5 more flexible
Timeout	`@Test(timeOut)`	`@Timeout` or `assertTimeout()`	Both functional
Parameterized tests	`@DataProvider`	`@ParameterizedTest`	Different paradigms

Detailed Feature Comparison

1. Parameterized Tests

TestNG with DataProvider:

@DataProvider(name = "loginData")
public Object[][] loginDataProvider() {
    return new Object[][] {
        {"user1", "pass1", true},
        {"user2", "wrongpass", false},
        {"", "pass3", false}
    };
}

@Test(dataProvider = "loginData")
public void testLogin(String username, String password, boolean shouldSucceed) {
    LoginPage page = new LoginPage();
    boolean result = page.login(username, password);
    assertEquals(result, shouldSucceed);
}

JUnit 5 with @ParameterizedTest:

@ParameterizedTest
@CsvSource({
    "user1, pass1, true",
    "user2, wrongpass, false",
    ", pass3, false"
})
void testLogin(String username, String password, boolean shouldSucceed) {
    LoginPage page = new LoginPage();
    boolean result = page.login(username, password);
    assertEquals(result, shouldSucceed);
}

// Alternative: @MethodSource for complex data
@ParameterizedTest
@MethodSource("loginDataProvider")
void testLoginMethodSource(String username, String password, boolean shouldSucceed) {
    // Test implementation
}

static Stream<Arguments> loginDataProvider() {
    return Stream.of(
        Arguments.of("user1", "pass1", true),
        Arguments.of("user2", "wrongpass", false),
        Arguments.of("", "pass3", false)
    );
}

Verdict: JUnit 5 offers more built-in sources (@CsvSource, @ValueSource, @EnumSource, @MethodSource), while TestNG’s @DataProvider is more flexible for complex scenarios.

2. Test Dependencies

TestNG:

@Test
public void testLogin() {
    // Login test
}

@Test(dependsOnMethods = "testLogin")
public void testAddToCart() {
    // This runs only if testLogin passes
}

@Test(dependsOnGroups = "sanity")
public void testCheckout() {
    // Runs after all tests in "sanity" group
}

JUnit 5:

JUnit 5 doesn’t support test dependencies by design. Tests should be independent. Use @TestMethodOrder for ordering:

@TestMethodOrder(OrderAnnotation.class)
class CheckoutFlowTest {

    @Test
    @Order(1)
    void testLogin() {
        // Login test
    }

    @Test
    @Order(2)
    void testAddToCart() {
        // Add to cart test
    }
}

Verdict: TestNG’s dependency management is powerful for integration tests where workflow order matters. JUnit 5 enforces better test isolation.

3. Parallel Execution

TestNG (testng.xml):

<!DOCTYPE suite SYSTEM "https://testng.org/testng-1.0.dtd">
<suite name="Parallel Suite" parallel="methods" thread-count="5">
    <test name="Regression">
        <classes>
            <class name="com.example.LoginTest"/>
            <class name="com.example.CheckoutTest"/>
        </classes>
    </test>
</suite>

Parallel execution options:

parallel="methods": Each test method in separate thread
parallel="classes": Each test class in separate thread
parallel="tests": Each <test> tag in separate thread

JUnit 5 (junit-platform.properties):

junit.jupiter.execution.parallel.enabled = true
junit.jupiter.execution.parallel.mode.default = concurrent
junit.jupiter.execution.parallel.config.strategy = dynamic

Programmatic control:

@Execution(ExecutionMode.CONCURRENT)
class ParallelTest {
    @Test
    void test1() { }

    @Test
    void test2() { }
}

Verdict: TestNG has more mature, XML-based parallel configuration. JUnit 5’s parallel execution is newer but improving rapidly.

4. Test Groups and Tagging

TestNG:

@Test(groups = {"sanity", "regression"})
public void testCriticalFeature() {
    // Test code
}

@Test(groups = "regression")
public void testSecondaryFeature() {
    // Test code
}

Run specific groups via testng.xml:

<test name="Sanity Tests">
    <groups>
        <run>
            <include name="sanity"/>
        </run>
    </groups>
    <classes>
        <class name="com.example.AllTests"/>
    </classes>
</test>

JUnit 5:

@Test
@Tag("sanity")
@Tag("regression")
void testCriticalFeature() {
    // Test code
}

@Test
@Tag("regression")
void testSecondaryFeature() {
    // Test code
}

Maven configuration:

<plugin>
    <artifactId>maven-surefire-plugin</artifactId>
    <configuration>
        <groups>sanity</groups>
    </configuration>
</plugin>

Verdict: Both offer similar functionality. TestNG’s XML-based approach is more flexible for complex test suite configurations.

5. Exception Testing

TestNG:

@Test(expectedExceptions = IllegalArgumentException.class,
      expectedExceptionsMessageRegExp = ".*invalid input.*")
public void testInvalidInput() {
    service.processInput("");
}

JUnit 5:

@Test
void testInvalidInput() {
    IllegalArgumentException exception = assertThrows(
        IllegalArgumentException.class,
        () -> service.processInput("")
    );
    assertTrue(exception.getMessage().contains("invalid input"));
}

Verdict: JUnit 5’s approach is more flexible, allowing assertions on the exception object.

6. Dynamic Tests

JUnit 5 Only:

@TestFactory
Stream<DynamicTest> dynamicTestsFromStream() {
    return Stream.of("apple", "banana", "orange")
        .map(fruit -> dynamicTest(
            "Test " + fruit,
            () -> assertFalse(fruit.isEmpty())
        ));
}

Verdict: JUnit 5 has native support for dynamic test generation at runtime. TestNG requires custom solutions.

Advanced Features Comparison

TestNG Unique Features

1. Suite-level Configuration:

@BeforeSuite
public void setupDatabase() {
    // Runs once before entire test suite
}

@AfterSuite
public void cleanupDatabase() {
    // Runs once after entire test suite
}

2. Flexible Test Configuration:

@Test(invocationCount = 5, threadPoolSize = 3)
public void stressTest() {
    // Runs 5 times with 3 concurrent threads
}

@Test(successPercentage = 80)
public void flakyTest() {
    // Passes if 80% of invocations succeed
}

3. Built-in Retry Logic:

public class RetryAnalyzer implements IRetryAnalyzer {
    private int retryCount = 0;
    private static final int maxRetryCount = 3;

    @Override
    public boolean retry(ITestResult result) {
        if (retryCount < maxRetryCount) {
            retryCount++;
            return true;
        }
        return false;
    }
}

@Test(retryAnalyzer = RetryAnalyzer.class)
public void unstableTest() {
    // Will retry up to 3 times on failure
}

JUnit 5 Unique Features

1. Nested Tests:

@DisplayName("Shopping Cart Tests")
class ShoppingCartTest {

    @Nested
    @DisplayName("When cart is empty")
    class EmptyCart {
        @Test
        void shouldHaveZeroItems() { }

        @Test
        void shouldHaveZeroTotal() { }
    }

    @Nested
    @DisplayName("When cart has items")
    class NonEmptyCart {
        @BeforeEach
        void addItems() { }

        @Test
        void shouldCalculateCorrectTotal() { }
    }
}

2. Conditional Test Execution:

@Test
@EnabledOnOs(OS.LINUX)
void onlyOnLinux() { }

@Test
@EnabledIfSystemProperty(named = "env", matches = "prod")
void onlyInProduction() { }

@Test
@EnabledIfEnvironmentVariable(named = "CI", matches = "true")
void onlyInCI() { }

3. Extension Model:

@ExtendWith(TimingExtension.class)
class PerformanceTest {
    @Test
    void fastOperation() { }
}

// Custom extension
public class TimingExtension implements BeforeTestExecutionCallback, AfterTestExecutionCallback {
    @Override
    public void beforeTestExecution(ExtensionContext context) {
        // Start timer
    }

    @Override
    public void afterTestExecution(ExtensionContext context) {
        // Log execution time
    }
}

Decision Matrix

Use Case	Recommendation	Reasoning
New Java project	JUnit 5	Modern architecture, active development
Spring Boot project	JUnit 5	Native Spring support, better integration
Complex test suites with dependencies	TestNG	Superior dependency management
Large enterprise projects	TestNG	Mature XML configuration, suite management
Microservices testing	JUnit 5	Better modularity, lighter weight
End-to-end integration tests	TestNG	Workflow dependencies, suite-level hooks
CI/CD with Jenkins	Both	Equal support
Selenium WebDriver tests	Both	Equal capabilities
API testing	Both	Equal capabilities
Mobile testing (Appium)	TestNG	Better parallel execution control

Migration Guide: TestNG to JUnit 5

Step 1: Update Dependencies

Replace TestNG with JUnit 5 in pom.xml:

<!-- Remove -->
<dependency>
    <groupId>org.testng</groupId>
    <artifactId>testng</artifactId>
</dependency>

<!-- Add -->
<dependency>
    <groupId>org.junit.jupiter</groupId>
    <artifactId>junit-jupiter</artifactId>
    <version>5.10.1</version>
    <scope>test</scope>
</dependency>

Step 2: Update Annotations

TestNG	JUnit 5 Equivalent
`@BeforeClass`	`@BeforeAll` (make method static)
`@AfterClass`	`@AfterAll` (make method static)
`@BeforeMethod`	`@BeforeEach`
`@AfterMethod`	`@AfterEach`
`@Test(enabled=false)`	`@Disabled`

Step 3: Replace DataProviders

Before (TestNG):

@DataProvider
public Object[][] testData() {
    return new Object[][] {{"test1"}, {"test2"}};
}

@Test(dataProvider = "testData")
public void test(String input) { }

After (JUnit 5):

@ParameterizedTest
@ValueSource(strings = {"test1", "test2"})
void test(String input) { }

Step 4: Handle Test Dependencies

Replace dependsOnMethods with proper test isolation or use @TestMethodOrder:

@TestMethodOrder(MethodOrderer.OrderAnnotation.class)
class OrderedTests {
    @Test
    @Order(1)
    void firstTest() { }

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

Performance Considerations

Startup Time

JUnit 5: Faster startup due to lazy loading
TestNG: Slightly slower but negligible in most cases

Execution Speed

Both frameworks have similar execution speeds. Differences are usually project-specific.

Memory Footprint

JUnit 5: Smaller footprint, modular design
TestNG: Slightly larger but includes more built-in features

Community and Ecosystem

JUnit 5

Adoption: Widely adopted, especially in Spring ecosystem
Documentation: Comprehensive official documentation
Integration: Excellent IDE support (IntelliJ, Eclipse, VS Code)
Plugins: Extensive Maven/Gradle plugin support

TestNG

Adoption: Strong in Selenium and enterprise automation
Documentation: Good documentation, many third-party resources
Integration: Good IDE support, mature tooling
Plugins: Robust plugin ecosystem

Conclusion

Choose JUnit 5 if:

Starting a new project
Using Spring Boot
Prefer modern Java features
Want lighter dependency footprint
Value strict test independence

Choose TestNG if:

Managing complex test suites with dependencies
Need suite-level configuration hooks
Require flexible parallel execution control
Working with legacy enterprise systems
Prefer XML-based test configuration

Both frameworks are production-ready and capable. The choice often depends on team familiarity, existing infrastructure, and specific project requirements. Many organizations successfully use both frameworks in different projects based on use case appropriateness.