Accessibility (A11y) testing in Nightwatch

Overview

In a bid to standardise accessibility testing, W3C has released the Web Content Accessibility Guidelines (WCAG) to standardise the practice of making websites inclusive to all. Since v2.3, accessibility testing support is now built-in to Nightwatch, using the aXe-core package developed by Deque Systems.

Accessibility tests audit the rendered DOM against a set of heuristics based on WCAG rules and other industry-accepted best practices. The aXe library has over 90 different around accessibility testing and automatically catches up to 57% of WCAG issues.

Run all rules

Use the command .axeInject() to inject the aXe library first and the simply run all accessibility tests with axeRun() command as shown below:

describe('accessibility testing', function() {
  

  it('run all accessibility rules', function(browser) {
    browser
      .navigateTo('https://www.w3.org/WAI/demos/bad/after/home.html')
      .axeInject()
      .axeRun('body');
  });
});

Run selected rules

Alternatively, you can choose to run only a selected tests, by passing the rule IDs in an array as shown below:

describe('accessibility testing', function() {
  

  it('accessibility rule subset', function(browser) {
    browser
      .navigateTo('https://www.w3.org/WAI/demos/bad/after/home.html')
      .axeInject()
      .axeRun('body', {
        runOnly: ['color-contrast', 'image-alt'],
      });
  });
});

Disable selected rules

You can also choose to run all the tests and exclude a few tests.

describe('accessibility testing', function() {
  

  it('accessibility rule subset', function(browser) {
    browser
      .navigateTo('https://www.w3.org/WAI/demos/bad/after/home.html')
      .axeInject()
      .axeRun('body', {
        rules: {
            'color-contrast': {
                enabled: false
            },
            'region': {
                enabled: false
            }
        }
    });
  });
});

You can find the complete list of the rule IDs on the Axe Github page

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