BiDi Accessibility Testing

Detailed explanation

Bidirectional (BiDi) accessibility testing is a crucial aspect of software localization and internationalization, ensuring that applications can properly display and handle text that contains both left-to-right (LTR) and right-to-left (RTL) scripts. Languages such as Arabic, Hebrew, Persian, and Urdu are written RTL, and when these languages are mixed with LTR languages like English, the text direction needs to be handled correctly to ensure readability and usability. BiDi accessibility testing goes beyond simply translating the text; it involves verifying the layout, mirroring of UI elements, and proper handling of mixed-direction content.

Understanding the Challenges

The primary challenge in BiDi support lies in the inherent complexity of mixing LTR and RTL text within the same document or user interface. This mixing can occur at various levels:

• Character Level: Individual characters can have different directions (e.g., numbers and punctuation within RTL text).
• Word Level: Words from different languages can be interspersed.
• Paragraph Level: Entire paragraphs can be written in different directions.
• UI Element Level: The layout of UI elements themselves may need to be mirrored.

Incorrect handling of BiDi text can lead to several issues, including:

• Text Display Errors: Characters appearing in the wrong order, garbled text, or incorrect line breaks.
• Layout Issues: UI elements being misaligned or overlapping.
• Usability Problems: Difficulty in reading and interacting with the application.
• Accessibility Concerns: Users with visual impairments who rely on screen readers may encounter difficulties navigating and understanding the content.

Practical Implementation and Best Practices

To effectively implement BiDi accessibility testing, consider the following best practices:

1. Locale Awareness: Ensure your application is locale-aware and can correctly identify and apply the appropriate BiDi settings based on the user's locale. Most operating systems and development frameworks provide built-in support for locale handling.

2. Unicode Support: Use Unicode encoding (UTF-8) throughout your application to support a wide range of characters from different languages.

3. CSS Styling: Utilize CSS properties specifically designed for BiDi support:

   • direction: Specifies the base text direction (e.g., rtl or ltr).
   • unicode-bidi: Controls how bidirectional text is handled within an element. Common values include normal, embed, bidi-override, and isolate.
   • text-align: Controls the alignment of text within an element. For RTL languages, text-align: right is typically used.

   Example:

   body {
     direction: rtl;
     unicode-bidi: embed;
     text-align: right;
   }

4. Logical Properties: Use logical CSS properties instead of physical properties for layout. Logical properties adapt to the text direction, making your application more flexible and maintainable. For example, use margin-inline-start instead of margin-left and padding-inline-end instead of padding-right.

   Example:

   .container {
     margin-inline-start: 10px; /* Adapts to left margin in LTR, right margin in RTL */
     padding-inline-end: 20px;   /* Adapts to right padding in LTR, left padding in RTL */
   }

5. Mirroring UI Elements: Mirror the layout of UI elements for RTL languages. This includes reversing the order of elements, flipping icons, and adjusting the alignment of text and controls.

   Example:

   In LTR: [Icon] Text [Button]

   In RTL: [Button] Text [Icon]

   CSS transforms can be used to flip icons:

   .rtl .icon {
     transform: scaleX(-1);
   }

6. Testing Tools and Techniques:

   • Manual Testing: Manually test your application with RTL languages to identify any display or layout issues. Use a virtual machine or emulator configured with an RTL locale.
   • Automated Testing: Automate BiDi testing using tools like Selenium or Cypress. These tools can be used to verify the layout, text direction, and functionality of your application in RTL environments.
   • Pseudo-Localization: Use pseudo-localization to simulate RTL languages by replacing LTR characters with RTL characters. This can help identify potential BiDi issues early in the development process.
   • Browser Developer Tools: Use browser developer tools to inspect the CSS properties and layout of your application in RTL mode.

7. Screen Reader Compatibility: Ensure that your application is compatible with screen readers in RTL languages. Screen readers should be able to correctly announce the text direction and navigate the UI elements. Use ARIA attributes to provide additional context to screen readers.

   Example:

   <div dir="rtl" aria-label="Arabic text">...</div>

8. Database Considerations: When storing BiDi text in a database, ensure that the database supports Unicode encoding and that the collation settings are appropriate for the languages you are supporting.

9. Collaboration with Localization Experts: Work closely with localization experts who have experience with BiDi languages. They can provide valuable insights and guidance on how to best support these languages in your application.

Common Tools

• Selenium/WebDriver: For automated UI testing, Selenium allows you to control browsers and simulate user interactions in different locales.
• Cypress: Another popular JavaScript-based end-to-end testing framework that can be used for BiDi testing.
• Browser Developer Tools: Chrome, Firefox, and other browsers provide developer tools that allow you to inspect the CSS properties and layout of your application in RTL mode. You can also use these tools to simulate different locales.
• Appium: For mobile app testing, Appium supports testing on both Android and iOS devices in RTL locales.

By following these best practices and utilizing appropriate testing tools, you can ensure that your application is accessible and usable for users who speak BiDi languages. This will not only improve the user experience but also expand your application's reach to a wider audience.

Further reading

• W3C Internationalization Best Practices for HTML: https://www.w3.org/International/techniques/authoring-html
• MDN Web Docs - Bidirectional text in HTML: https://developer.mozilla.org/en-US/docs/Web/HTML/Bi-directional_text
• CSS Logical Properties and Values: https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Logical_Properties_and_Values