🧪 Unit Test

TestNG

1. Prerequisites

• Java Development Kit (JDK) 21 installed.

• Apache Maven installed.

• An IDE (IntelliJ IDEA, Eclipse, or VS Code).

2. Create a Maven Project

You can create a new Maven project using your IDE or via the command line:

mvn archetype:generate -DgroupId=com.example -DartifactId=testng-demo -DarchetypeArtifactId=maven-archetype-quickstart -DinteractiveMode=false

3. Configure pom.xml

Open pom.xml and add the TestNG dependency. Ensure the compiler source and target are set to 21.

<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>testng-demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>21</maven.compiler.source>
        <maven.compiler.target>21</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <!-- TestNG Dependency -->
        <dependency>
            <groupId>org.testng</groupId>
            <artifactId>testng</artifactId>
            <version>7.10.1</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

4. Create a Class to Test

Create a simple Calculator class in src/main/java/com/example/Calculator.java.

package com.example;

public class Calculator {
    public int add(int a, int b) {
        return a + b;
    }

    public int subtract(int a, int b) {
        return a - b;
    }
}

5. Write a TestNG Test

Create a test class in src/test/java/com/example/CalculatorTest.java.

package com.example;

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

public class CalculatorTest {
    private Calculator calculator;

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

    @Test
    public void testAdd() {
        int result = calculator.add(5, 3);
        Assert.assertEquals(result, 8, "5 + 3 should equal 8");
    }

    @Test
    public void testSubtract() {
        int result = calculator.subtract(10, 4);
        Assert.assertEquals(result, 6, "10 - 4 should equal 6");
    }
}

6. Run the Tests

You can run the tests using the Maven command:

mvn test

Jest

1. Prerequisites

• Node.js installed (includes npm).

• An IDE (VS Code recommended).

2. Initialize a Node.js Project

Create a new folder for your project and initialize it:

mkdir jest-demo
cd jest-demo
npm init -y

3. Install Jest

Install Jest as a development dependency:

npm install --save-dev jest

4. Configure package.json

Open package.json and change the test script to run jest:

{
  "scripts": {
    "test": "jest"
  }
}

5. Create a Function to Test

Create a file named sum.js:

function sum(a, b) {
  return a + b;
}
module.exports = sum;

6. Write a Jest Test

Create a file named sum.test.js:

const sum = require('./sum');

test('adds 1 + 2 to equal 3', () => {
  expect(sum(1, 2)).toBe(3);
});

7. Run the Tests

Run the following command in your terminal:

npm test