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A vertical-slice TDD workflow: write one test, implement minimally, refactor, and repeat — focusing on behavior through public interfaces rather than implementa
EvanFlow: TDD prescribes a disciplined test-driven development cycle focused on vertical slices. Each cycle is RED (write a failing test), GREEN (implement minimal code to pass), and REFACTOR (clean while tests are fresh). The skill documents vocabulary, anti-patterns, and a per-cycle checklist to enforce behavior-driven assertions and real-service integration where possible.
Use it for developing production features, bug fixes, or refactors where behavioral guarantees matter. It's intended for backend services, business logic, and frontend code with testable behavior — avoid for throwaway prototypes or generated code. Use when you want tight feedback, safer refactors, and tests that describe observable behavior rather than internals.
Suited to developer-assistant frameworks that can run tests and interact with repositories or CI (Claude Code, Codex-like agents, or CLI-capable tooling).
A vertical-slice TDD workflow skill with no bundled scripts. Well-structured instructions emphasizing behavior testing over implementation testing, with an excellent assertion-correctness warning section. Clean security profile — pure instruction text with no executable code, network calls, or credentials.
The assertion-correctness warning section (citing HumanEval research on LLM-generated test assertions) is a standout feature. The anti-pattern guidance on horizontal vs vertical slicing is practical and well-articulated.