accessibility-standards.md

Accessibility Standards for AL Development

This document outlines rules for procedure accessibility in AL files to ensure proper testability, maintainability, and proper encapsulation practices in Business Central development.

Procedure Accessibility Rules

1. Internal Procedures: Internal procedures in the main app should remain internal. They are accessible to the test app and do not need to be made public.
2. Do Not Use Local Procedures: Do not use local procedures, as they cannot be accessed or tested from the test app. All procedures that need to be accessed from the test app should be marked as internal.

Best Practices for Testability

Access Control Guidelines

• Use internal procedures instead of local for better testability
• Keep procedures internal unless they need to be exposed to other extensions
• Make procedures public only when they form part of the extension's public API
• Document the intended accessibility level in procedure comments

Testing Considerations

• Design procedures with testing in mind from the start
• Ensure critical business logic is accessible to test codeunits
• Use dependency injection patterns where appropriate for external dependencies
• Consider creating test-specific interfaces for complex integrations

Encapsulation Balance

• Maintain proper encapsulation while ensuring testability
• Group related procedures logically within codeunits
• Use clear naming conventions that indicate the intended usage scope
• Document public interfaces thoroughly for consumers

By following these accessibility standards, you ensure that your code remains testable while maintaining proper encapsulation and access control throughout your AL development workflow.