Testing

A disciplined approach to verifying that software behaves correctly, remains stable under change, and communicates intent to future developers. Good tests act as living documentation, a safety net for refactoring, and a design feedback mechanism.

This skill covers universal testing concepts that apply regardless of language, framework, or tooling.

When to Use

• Designing a test strategy for a new project or feature
• Deciding what level of testing (unit, integration, e2e) a piece of code needs
• Evaluating whether existing tests are providing value or creating drag
• Applying TDD to drive design decisions
• Debugging a flaky or brittle test suite
• Reviewing test code for quality and maintainability

Testing Pyramid

The testing pyramid describes the ideal distribution of tests across three levels. More tests at the base, fewer at the top.