Testing Requirements

Testing requirements define what test coverage components must have before acceptance into design systems. Comprehensive testing requirements ensure component reliability while establishing clear expectations for contributors.

What Are Testing Requirements

Testing requirements specify the types and extent of testing that design system components must include. Requirements typically address unit testing, integration testing, visual testing, accessibility testing, and coverage thresholds. Clear requirements ensure consistent test quality across all components.

Testing serves multiple purposes in design systems. Tests verify component correctness. They catch regressions during maintenance. They document expected behavior. They provide confidence during refactoring. Design system components, used across many applications, benefit especially from thorough testing given their broad impact.

How Testing Requirements Work

Unit testing requirements specify that components must have tests verifying their core functionality. Tests should cover different states, prop variations, and edge cases. Unit tests execute quickly, providing rapid feedback during development and review.

Visual testing requirements ensure components render correctly across scenarios. Snapshot testing or visual regression testing captures expected appearance and detects unintended changes. Visual tests catch styling regressions that functional tests might miss.

Accessibility testing requirements verify compliance through automated testing. Accessibility testing tools detect common violations like missing labels, insufficient contrast, and keyboard issues. While automated testing cannot catch all accessibility issues, it provides valuable baseline coverage.

Integration testing requirements verify component behavior in realistic contexts. Tests examine how components interact with each other and with consumer code. Integration tests catch issues that unit tests of isolated components might miss.

Coverage requirements set minimum thresholds for test coverage metrics. Common thresholds range from 70% to 90% coverage. While coverage metrics have limitations, they provide objective baselines that prevent untested code from entering the system.

Key Considerations

• Requirements should be achievable while maintaining meaningful quality standards
• Different component types may warrant different testing approaches
• Test maintenance burden should be considered when setting requirements
• Testing requirements should evolve with testing capabilities and practices
• Exceptions should be rare and justified

Common Questions

What coverage levels are appropriate?

Coverage levels depend on component criticality and organizational standards. Core components used widely often warrant higher coverage than specialized components. 80% coverage represents a common balance between thoroughness and practicality. However, coverage numbers should not be pursued at the expense of meaningful tests; low-value tests that inflate coverage provide false confidence.

Should visual testing be required for all components?

Visual testing provides significant value for design systems where visual consistency matters. Most organizations require visual tests for components with meaningful visual output. Pure logic components or utilities may not need visual testing. The requirement should match what the component does and how it might regress.

How do testing requirements affect contribution friction?

Testing requirements add work for contributors but protect long-term quality. Organizations should balance requirements against contribution friction. Good testing infrastructure and clear examples reduce the burden of meeting requirements. Requirements that are too onerous may discourage valuable contributions; requirements that are too lax allow quality problems.

Summary

Testing requirements establish minimum test coverage standards for design system components. Success requires clear expectations, appropriate thresholds, and testing infrastructure that enables contributors to meet requirements efficiently. Organizations should invest in testing requirements that protect quality while remaining achievable.