TestNG Setup and Basic Usage

To begin using TestNG in a Java project, configure your environment with Maven. Add the following dependency to your pom.xml file:

<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example</groupId>
    <artifactId>TestProject</artifactId>
    <version>1.0</version>
    <dependencies>
        <dependency>
            <groupId>org.testng</groupId>
            <artifactId>testng</artifactId>
            <version>7.4.0</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

After adding the dependency, create a test class in your IDE. Use the @Test annotation to mark test methods. For example:

import org.testng.annotations.Test;

public class SampleTest {
    @Test
    public void verifyAddition() {
        System.out.println("Executing addition test");
    }
}

Run the test class directly from your IDE or via Maven commands.

Key TestNG Annotations

TestNG provides several annnotations to control test execution flow:

Annotation	Purpose
@BeforeSuite	Executes once before all tests in the suite
@AfterSuite	Executes once after all tests in the suite
@BeforeTest	Runs before any test method in a <test> tag
@AfterTest	Runs after all test methods in a <test> tag
@BeforeClass	Executes before the first test method in the current class
@AfterClass	Executes after all test methods in the current class
@BeforeMethod	Runs before each test method
@AfterMethod	Runs after each test method
@DataProvider	Suplies data to test methods
@Factory	Creates test class instances dynamically
@Listeners	Defines custom listeners for test events
@Parameters	Passes parameters from XML configurasion
@Test	Marks a method as a test case

Here's an example demonstrating execution order:

import org.testng.annotations.*;

public class AnnotationDemo {
    @BeforeSuite
    public void setupSuite() {
        System.out.println("Suite setup");
    }
    
    @BeforeClass
    public void setupClass() {
        System.out.println("Class setup");
    }
    
    @BeforeMethod
    public void setupMethod() {
        System.out.println("Method setup");
    }
    
    @Test
    public void testOne() {
        System.out.println("Test one execution");
    }
    
    @Test
    public void testTwo() {
        System.out.println("Test two execution");
    }
    
    @AfterMethod
    public void cleanupMethod() {
        System.out.println("Method cleanup");
    }
    
    @AfterClass
    public void cleanupClass() {
        System.out.println("Class cleanup");
    }
    
    @AfterSuite
    public void cleanupSuite() {
        System.out.println("Suite cleanup");
    }
}

Execution output:

Suite setup
Class setup
Method setup
Test one execution
Method cleanup
Method setup
Test two execution
Method cleanup
Class cleanup
Suite cleanup

Assertions in TestNG

TestNG includes assertion methods for validation:

• assertEquals(actual, expected) - Verifies equality
• assertNotEquals(actual, unexpected) - Verifies inequality
• assertTrue(condition) - Checks if condition is true
• assertFalse(condition) - Checks if condition is false
• assertNull(object) - Verifies object is null
• assertNotNull(object) - Verifies object is not null
• assertSame(expected, actual) - Checks object references
• assertNotSame(unexpected, actual) - Verifies different references
• assertArrayEquals(expectedArray, actualArray) - Compares arrays

Example usage:

import org.testng.Assert;
import org.testng.annotations.Test;

public class AssertionExamples {
    @Test
    public void validateCalculations() {
        int result = 5 + 3;
        Assert.assertEquals(result, 8, "Addition should return 8");
        Assert.assertNotEquals(result, 10, "Result should not be 10");
        Assert.assertTrue(result > 0, "Result should be positive");
    }
}

Running Tests with Maven

Configure the Maven Surefire plugin to execute TestNG tests:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-surefire-plugin</artifactId>
            <version>3.0.0-M5</version>
            <configuration>
                <suiteXmlFiles>
                    <suiteXmlFile>testng.xml</suiteXmlFile>
                </suiteXmlFiles>
            </configuration>
        </plugin>
    </plugins>
</build>

Test Configuration Options

Disabling Tests

Use enabled = false to skip test execution:

@Test(enabled = false)
public void disabledTest() {
    System.out.println("This won't run");
}

Timeout Configuration

Set maximum execution time with timeOut:

@Test(timeOut = 2000)
public void timeLimitedTest() throws InterruptedException {
    Thread.sleep(1500); // Passes within timeout
}

@Test(timeOut = 500)
public void failingTimeoutTest() {
    while(true) {} // Exceeds timeout, fails
}

Grouping Tests

Organize tests into groups for selective execution:

@Test(groups = {"smoke", "regression"})
public void smokeAndRegressionTest() {
    System.out.println("Running smoke and regression test");
}

@Test(groups = "regression")
public void regressionOnlyTest() {
    System.out.println("Running regression test");
}

Configure group execution in testng.xml:

<!DOCTYPE suite SYSTEM "https://testng.org/testng-1.0.dtd">
<suite name="TestSuite">
    <test name="RegressionTests">
        <groups>
            <run>
                <include name="regression"/>
            </run>
        </groups>
        <classes>
            <class name="com.example.TestClass"/>
        </classes>
    </test>
</suite>

Test Execution Order

Control method execution sequence with priority:

@Test(priority = 1)
public void firstTest() {
    System.out.println("First to execute");
}

@Test(priority = 3)
public void thirdTest() {
    System.out.println("Third to execute");
}

@Test(priority = 2)
public void secondTest() {
    System.out.println("Second to execute");
}

Test Dependencies

Define dependencies between test methods:

@Test
public void prerequisiteTest() {
    System.out.println("Must run first");
}

@Test(dependsOnMethods = "prerequisiteTest")
public void dependentTest() {
    System.out.println("Runs after prerequisite");
}

If the prerequisite test fails, dependent tests are skipped.

Parameterized Testing

XML-Based Parameters

Pass parameters through test configuration:

@Test
@Parameters({"username", "password"})
public void loginTest(String user, String pass) {
    System.out.println("Testing login with: " + user + "/" + pass);
}

testng.xml configuration:

<suite name="ParameterSuite">
    <test name="LoginTests">
        <parameter name="username" value="testuser"/>
        <parameter name="password" value="secret123"/>
        <classes>
            <class name="com.example.LoginTests"/>
        </classes>
    </test>
</suite>

DataProvider Parameters

Use @DataProvider for complex parameter sets:

@DataProvider(name = "userCredentials")
public Object[][] provideUserData() {
    return new Object[][] {
        {"alice", "alice123"},
        {"bob", "bob456"},
        {"charlie", "charlie789"}
    };
}

@Test(dataProvider = "userCredentials")
public void multiUserLogin(String username, String password) {
    System.out.println("Testing: " + username);
}

This executes the test method three times with different data sets.