test-driven-development
Drives development with tests. Use when implementing any logic, fixing any bug, or changing any behavior. Use when you need to prove that code works, when a bug report arrives, or when you're about to modify existing functionality.
Security Assessment
About test-driven-development
The test-driven-development skill facilitates a disciplined approach to software development by ensuring that tests drive the coding process. Its core principle is to write a failing test before implementing the corresponding functionality, providing immediate verification that the code behaves as intended. This approach minimizes the risk of regressions, increases confidence in bug fixes, and provides concrete proof that new features meet their requirements. By integrating tests into the workflow, this skill transforms codebases into more maintainable and reliable systems, allowing developers to avoid the pitfalls of relying solely on intuition or assumptions about code correctness.
Key features of this skill include structured guidance through the Test-Driven Development (TDD) cycle, which consists of writing a failing test (RED), implementing the minimal code to pass the test (GREEN), and refining the code while keeping tests passing (REFACTOR). It emphasizes the Prove-It Pattern for bug fixes, where developers reproduce the bug through a test before applying a fix, ensuring that regressions are caught and resolved. The skill also encourages adherence to testing best practices, such as focusing on small, fast unit tests and progressively fewer high-level tests, aligning with the test pyramid concept. Code examples in TypeScript illustrate practical implementation of these steps, showing how tests validate task creation and bug resolution scenarios.
Typical use cases include developing new functionality, fixing existing bugs, modifying behavior safely, and handling edge cases in a codebase. It is particularly valuable for developers working in environments where code correctness and maintainability are critical, such as web applications, APIs, or any system with complex logic. Target users are software engineers, quality assurance professionals, and technical teams who want to integrate systematic testing into their development workflow to increase confidence in changes, prevent regressions, and maintain high code quality.
FAQ
When should I use the test-driven-development skill?
Use it when implementing new logic, fixing bugs, modifying existing functionality, or handling edge cases. Avoid it for pure configuration changes, documentation updates, or static content changes with no behavioral impact.
Which programming languages are supported?
The examples provided use TypeScript, but the principles of test-driven development can be applied to any language that supports automated testing.
Do I need an existing test framework?
Yes, you should have a test framework available to write and run tests, as TDD relies on writing failing tests before implementing code.
How does this skill handle bug fixes?
It uses the Prove-It Pattern, where a test reproduces the bug first, then the code is modified to pass the test, ensuring the fix works and preventing regressions.
Can TDD be used for browser-based changes?
Yes, for browser-based changes, TDD can be combined with runtime verification tools, such as Chrome DevTools MCP, to validate behavior.
Install test-driven-development
Quick Setup:
- Copy the skill folder to
.claude/skills/ - Claude will automatically detect and use the skill
Repository
addyosmani/agent-skills