#8 by installsTesting & QA
tdd
Test-driven development. Use when the user wants to build features or fix bugs test-first, mentions "red-green-refactor", or wants integration tests.
1.1M
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276.1K
Feb 10, 2026
Install
npx skills add https://github.com/mattpocock/skills --skill tddWhat it does
Test-driven development with vertical slices, behavior-focused tests, and incremental red-green-refactor cycles. Test-driven development. Use when the user wants to build features or fix bugs test-first, mentions "red-green-refactor", or wants integration tests.
- Emphasizes integration-style tests that verify behavior through public APIs, not implementation details; tests should survive refactors unchanged
- Requires vertical slicing (one test → one implementation → repeat) instead of horizontal slicing (all tests first, then all code), preventing brittle, behavior-insensitive test suites
- Includes planning phase to confirm interface changes, prioritize behaviors to test, and design for testability before writing code
