Automated Accessibility Testing: A Comprehensive Guide

Shawn Sandy (Ally.Cafe) ~ June 27, 2024

Automated accessibility testing plays a critical role in identifying and fixing common accessibility issues in web development. While it cannot replace manual testing, automated tools can significantly streamline the process and ensure that many basic accessibility requirements are met efficiently. This guide will explore the importance of automated testing, introduce some popular tools, and provide best practices for integrating automated testing into your workflow.

Why Automated Testing is Important

Automated accessibility testing is important because it:

Increases Efficiency: Quickly identifies common accessibility issues across large websites.
Ensures Consistency: Applies consistent standards and checks that can be difficult to maintain manually.
Saves Time: Automates repetitive tasks, allowing developers to focus on more complex issues.
Provides Early Detection: Catches issues early in the development process, reducing the cost and effort required to fix them later.

Popular Automated Testing Tools

Several tools are available to help automate accessibility testing. Here are some of the most widely used:

1. Axe by Deque

Overview: Axe is a powerful, open-source accessibility testing tool that integrates with browsers and development environments.

Features:

Browser extensions for Chrome and Firefox.
Integrations with popular development tools and CI/CD pipelines.
Detailed reports on accessibility issues.

Usage:

Install the Axe browser extension.
Open the web page you want to test.
Run the Axe analysis and review the results.

Example:

// Example code snippet to include Axe in automated tests
const { AxePuppeteer } = require('axe-puppeteer');
const puppeteer = require('puppeteer');

(async () => {
  const browser = await puppeteer.launch();
  const page = await browser.newPage();
  await page.goto('http://example.com');
  const results = await new AxePuppeteer(page).analyze();
  console.log(results);
  await browser.close();
})();

2. WAVE by WebAIM

Overview: WAVE is a suite of evaluation tools that help authors make their web content more accessible.

Features:

Browser extensions for Chrome and Firefox.
Online accessibility checker.
Detailed visual feedback on accessibility issues.

Usage:

Install the WAVE browser extension.
Open the web page you want to test.
Run the WAVE analysis and review the results.

3. Lighthouse by Google

Overview: Lighthouse is an open-source tool by Google that helps improve the quality of web pages, including accessibility.

Features:

Integrated with Chrome DevTools.
Provides scores and recommendations for accessibility.
CLI and Node module for integration into build processes.

Usage:

Open Chrome DevTools.
Navigate to the “Lighthouse” tab.
Run an accessibility audit and review the results.

Example:

// Example code snippet to include Lighthouse in automated tests
const lighthouse = require('lighthouse');
const chromeLauncher = require('chrome-launcher');

(async () => {
  const chrome = await chromeLauncher.launch({ chromeFlags: ['--headless'] });
  const options = { port: chrome.port };
  const runnerResult = await lighthouse('http://example.com', options);

  console.log(runnerResult.lhr.categories.accessibility.score);
  await chrome.kill();
})();

Best Practices for Automated Testing

Integrate Early and Often

Integrate automated accessibility testing early in the development process and run tests frequently. This practice helps identify and resolve issues before they become deeply embedded in the codebase.

Combine Automated and Manual Testing

While automated tools are powerful, they cannot catch every accessibility issue. Combine automated testing with manual testing to ensure comprehensive coverage.

Use Multiple Tools

Different tools may catch different issues. Using multiple tools can provide a more thorough assessment of your website’s accessibility.

Focus on High-Impact Issues

Prioritize fixing issues that have the most significant impact on users. Automated tools often rank issues by severity, which can help guide your efforts.

Regularly Update Tools

Ensure that your testing tools are up-to-date. Accessibility standards and best practices evolve, and using the latest versions of tools ensures you are testing against the most current guidelines.

Example Workflow

Here’s an example workflow that incorporates automated accessibility testing:

Development Phase:
- Use Axe or Lighthouse during development to catch issues early.
- Run automated tests as part of the build process.
Testing Phase:
- Conduct a full site scan using WAVE or a similar tool.
- Review and address the reported issues.
Pre-Launch Phase:
- Perform a final automated scan using multiple tools.
- Conduct manual testing to ensure comprehensive coverage.
Post-Launch Phase:
- Regularly schedule automated tests to catch new issues as the site evolves.
- Continuously monitor and address accessibility issues.

Conclusion

Automated accessibility testing is a vital part of creating inclusive web experiences. By leveraging powerful tools like Axe, WAVE, and Lighthouse, developers can efficiently identify and address many common accessibility issues. However, it is crucial to remember that automated testing should complement, not replace, manual testing. By integrating both approaches and following best practices, you can ensure your website is accessible to all users, including those with disabilities.

Useful Resources

For more information on automated accessibility testing, check out these resources:

By incorporating automated accessibility testing into your development process, you can create a more accessible web for everyone.

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