Multiple browsers open at the same time (Test Automation)

Why This Matters

In today's digital landscape, web applications are developed to cater to a diverse range of users across various devices and browsers. Ensuring cross-browser compatibility is essential for delivering an optimal user experience. Test automation with multiple browsers open simultaneously can help achieve this goal by improving test coverage, reducing test execution time, and identifying browser-specific issues early in the development process.

Test automation frameworks allow us to write scripts that mimic user interactions with web applications. However, when it comes to running multiple browsers concurrently during test automation, each tool has its unique approach. This lesson will focus on using JavaScript and popular test automation tools like Selenium, Cypress, and Playwright to run tests across various browsers simultaneously.

Prerequisites

To follow along with this lesson effectively, you should have a solid understanding of JavaScript, HTML, CSS, and one or more test automation frameworks such as Selenium, Cypress, or Playwright. Familiarity with browser-specific drivers for Selenium, like ChromeDriver and GeckoDriver, will also be beneficial.

Selenium

• JavaScript Selenium WebDriver
• ChromeDriver
• GeckoDriver

Cypress

• Cypress Documentation

Playwright

• Playwright Documentation

Core Concept

Test automation frameworks allow us to write scripts that mimic user interactions with web applications. However, when it comes to running multiple browsers concurrently during test automation, each tool has its unique approach.

Selenium

Selenium WebDriver supports multiple browsers through its browser-specific drivers (e.g., ChromeDriver, GeckoDriver). To run tests in parallel across different browsers, you can use Grid technology or third-party solutions like Sauce Labs or BrowserStack.

const {Builder, By, Key} = require('selenium-webdriver');

let chromeDriver = new Builder().forBrowser('chrome').build();
let firefoxDriver = new Builder().forBrowser('firefox').build();

async function runTest() {
await chromeDriver.get('https://example.com');
// Test in Chrome

await firefoxDriver.get('https://example.com');
// Test in Firefox
}

runTest().then(() => {
console.log("Tests completed.");
});

In this example, we create separate instances of Chrome and Firefox browsers using Selenium WebDriver and run tests on each browser instance.

Cypress

Cypress uses its own built-in browser for test execution, and it doesn't natively support running multiple browsers at the same time. However, you can use plugins like cypress-multiple-browsers to achieve this functionality.

// cypress/plugins/index.js
const MultipleBrowsers = require('cypress-multiple-browsers');

module.exports = (on, config) => {
on('before:browser:launch', MultipleBrowsers(config));
};

With the cypress-multiple-browsers plugin installed, you can run tests in multiple browsers by specifying the browser options in your test files.

Playwright

Playwright allows you to run tests in multiple browsers using the launch() function and its browser-specific options.

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

async function runTest() {
const chromeBrowser = await chromium.launch();
const firefoxBrowser = await firefox.launch();
// Test in Chrome and Firefox

await Promise.all([chromeBrowser.close(), firefoxBrowser.close()]);
}

runTest().catch(console.error).finally(() => console.log("Tests completed."));

In this example, we launch separate instances of Chrome and Firefox browsers using Playwright and run tests on each browser instance.

Worked Example

Let's create a test suite that runs tests in Chrome, Firefox, and Safari using Playwright.

1. Install Playwright: npm install playwright
2. Create a new file called index.js with the following content:

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

async function runTest() {
const chromeBrowser = await chromium.launch();
const firefoxBrowser = await firefox.launch();
const safariBrowser = await webkit.launch({ channel: 'safari' });

// Test in Chrome, Firefox, and Safari

await Promise.all([chromeBrowser.close(), firefoxBrowser.close(), safariBrowser.close()]);
}

runTest().catch(console.error).finally(() => console.log("Tests completed."));

1. Run the test suite: node index.js

In this example, we launch separate instances of Chrome, Firefox, and Safari browsers using Playwright and run tests on each browser instance.

Common Mistakes

• Forgetting to close browser instances after testing, leading to resource consumption.
• Solution: Always call the close() method on browser instances once you're done with them.
• Not handling browser-specific quirks or differences in test results across browsers.
• Solution: Use browser-specific selectors and workarounds for known issues.
• Failing to account for network latency when comparing test results between browsers.
• Solution: Implement a wait strategy that takes into account the average network latency differences between browsers.
• Ignoring the need for cross-browser testing, focusing only on a single browser.
• Solution: Always prioritize cross-browser testing to ensure your application works correctly across various browsers and devices.

Common Mistakes (additional subheadings)

• Inconsistent test results due to browser version differences.
• Solution: Ensure that all browsers used for testing have the same versions to avoid inconsistencies in test results.
• Browser-specific extensions or plugins affecting test outcomes.
• Solution: Disable or uninstall unnecessary browser extensions and plugins during test execution to maintain a consistent environment.

Practice Questions

1. How can you run tests in multiple browsers using Selenium WebDriver?

• Solution: Use Grid technology or third-party solutions like Sauce Labs or BrowserStack to run tests in parallel across different browsers with Selenium WebDriver.

1. What is the recommended approach to running parallel tests across different browsers with Cypress?

• Solution: Use plugins like cypress-multiple-browsers to achieve this functionality.

1. Write a Playwright script that runs tests in Chrome, Firefox, and Safari, and takes screenshots for each test case.

• Solution: Modify the previous example by adding a screenshot function after navigating to each test URL. You can use the page.screenshot() method to capture a screenshot of the current page.

FAQ

1. Why should I run multiple browsers during test automation?

• Answer: Running tests in multiple browsers helps ensure cross-browser compatibility, improves test coverage, and reduces test execution time by identifying inconsistencies and improving the overall user experience.

1. What are some common pitfalls when running tests in multiple browsers?

• Answer: Common pitfalls include handling browser-specific quirks, network latency differences, resource consumption due to forgotten browser instances, and ignoring the need for cross-browser testing. It's essential to account for these factors during test automation.

1. Can I run Playwright tests in parallel across different browsers?

• Answer: Yes, you can use the launch() function with browser-specific options to launch multiple Playwright browsers and run tests in parallel. However, keep in mind that running tests concurrently may consume more system resources.

1. How do I handle browser-specific selectors or workarounds for known issues when using Selenium WebDriver?

• Answer: Use browser-specific selectors to target elements based on their unique attributes, and implement workarounds for known issues by modifying the test script accordingly.

1. What is Grid technology in Selenium WebDriver, and how does it help with running tests across multiple browsers?

• Answer: Grid technology allows you to run tests in parallel across different nodes (machines) that have various browser versions installed. This helps improve test execution time and coverage by testing the application on a wide range of browser configurations.