Automating Java Web Application Testing with Playwright: A Step-by-Step Guide

Automated testing is a critical aspect of modern web development, ensuring that applications function correctly across different browsers and platforms. Among the various tools available for automated testing, Playwright stands out for its robustness and versatility. This blog post will explore when to use Playwright for test automation, its purpose and detailed steps to set up and use Playwright for automating the testing of a Java web application.

Introduction to Playwright

Playwright is an open-source test automation framework developed by Microsoft. It supports multiple programming languages, including JavaScript, TypeScript, Python, C#, and Java. Playwright allows to automate browser interactions for testing web applications across different browsers (Chrome, Firefox, and WebKit).

When to Use Playwright

Playwright is particularly useful in the following scenarios:

Cross-Browser Testing: Easily test web applications across multiple browsers (Chromium, Firefox, WebKit) to ensure compatibility and consistent behavior.

End-to-End Testing: For comprehensive end-to-end testing, simple and easy to simulate real user interactions to validate the entire flow of the application.

Responsive Design Testing: When verifying an application that works well on various screen sizes and devices.

Performance Testing: The performance of the web application under different conditions can be easily measured and analyzed.

Headless Testing: Tests can be executed in headless mode (without a graphical user interface) for faster execution in CI/CD pipelines.

Auto-Wait Mechanism: Playwright automatically waits for elements to be ready before interacting with them, reducing flaky tests and improving reliability.

Powerful Selectors: Supports a variety of selectors, including CSS, XPath, and text selectors, making it easier to locate elements.

Rich API: Playwright’s API supports advanced features such as network interception, screenshots, and video recording, providing detailed insights into test failures.

Language Support: Playwright supports multiple languages, including JavaScript, TypeScript, Python, C#, and Java, offering flexibility based on team’s expertise.

Parallel Execution: Supports parallel test execution, which can significantly reduce the overall test execution time.

Installing and configuring Playwright

Prerequisites

Start with installing below:

•            Node.js (v12 or later)

•            npm (Node package manager)

Step-by-Step Guide to Using Playwright for Java Web Application Testing

First, create a new directory for Playwright project and initialize a new Node.js project.

Step 1: Set Up the Sample Project

mkdir playwright-java-app

cd playwright-java-app

npm init -y

Step 2: Install Playwright

Next, install Playwright and its necessary dependencies.

npm install --save-dev playwright

Step 3: Create a Basic Test Script

Create a new directory called tests and add a test script file, for example, test.js.

mkdir tests

touch tests/test.js

Open test.js in code editor and add the following code:

const { chromium } = require('playwright');

(async () => {

    const browser = await chromium.launch();

    const context = await browser.newContext();

    const page = await context.newPage();

    // Navigate to the web application

    await page.goto('http://localhost:8080');

    // Interact with the web application

    await page.fill('#username', 'testuser');

    await page.fill('#password', 'password');

    await page.click('#loginButton');

    // Add assertions to verify the expected behavior

    await page.waitForSelector('#welcomeMessage');

    const welcomeMessage = await page.textContent('#welcomeMessage');

    console.assert(welcomeMessage === 'Welcome, testuser!', 'Login failed or welcome message is incorrect');

    await browser.close();

})();

Step 4: Run the Test Script

Ensure the Java web application is running locally, then execute the test script.

node tests/test.js

The script launches a browser, navigates to the web application's login page, fills in the login credentials, clicks the login button, and verifies the welcome message.

Step 5: Configure Playwright for Cross-Browser Testing

To test across multiple browsers, update the test.js script as follows:

const { chromium, firefox, webkit } = require('playwright');

const browsers = [chromium, firefox, webkit];

(async () => {

    for (const browserType of browsers) {

        const browser = await browserType.launch();

        const context = await browser.newContext();

        const page = await context.newPage();

        console.log(`Testing with ${browserType.name()}`);

        // Navigate to the web application

        await page.goto('http://localhost:8080');

        // Interact with the web application

        await page.fill('#username', 'testuser');

        await page.fill('#password', 'password');

        await page.click('#loginButton');

        // Add assertions to verify the expected behavior

        await page.waitForSelector('#welcomeMessage');

        const welcomeMessage = await page.textContent('#welcomeMessage');

        console.assert(welcomeMessage === 'Welcome, testuser!', 'Login failed or welcome message is incorrect');

        await browser.close();

    }

})();

This script will now run the tests sequentially in Chromium, Firefox, and WebKit browsers.

Step 6: Organize Tests with Playwright Test Runner

For better test organization and reporting, the Playwright Test Runner can be used, which can be installed as below:

npm install --save-dev @playwright/test

Update the test.js to use the Playwright Test Runner:

const { test, expect } = require('@playwright/test');

test.describe('Java Web Application Tests', () => {

    test('Login Test', async ({ page }) => {

        await page.goto('http://localhost:8080');

        await page.fill('#username', 'testuser');

        await page.fill('#password', 'password');

        await page.click('#loginButton');

        await page.waitForSelector('#welcomeMessage');

        const welcomeMessage = await page.textContent('#welcomeMessage');

        expect(welcomeMessage).toBe('Welcome, testuser!');

    });

});

Add a configuration file playwright.config.js to customize the test runner:

module.exports = {

    use: {

        browserName: 'chromium', // or 'firefox' or 'webkit'

        headless: false, // set to true for headless mode

    },

    testDir: './tests',

};

Run the tests using the Playwright Test Runner:

npx playwright test

Conclusion

By following these steps, Playwright can be efficiently set up to automate the testing of Java web application.

Playwright is a powerful tool for automated testing, offering extensive features and multi-browser support. It is ideal for teams that need to perform comprehensive end-to-end testing, ensure cross-browser compatibility, and integrate testing into CI/CD pipelines. While there is a learning curve and resource considerations, the benefits of using Playwright can significantly enhance the reliability and efficiency of the web application testing efforts.