test-writer

Test-driven development for existing code starts by writing failing tests that specify desired behavior, then implementing or refactoring code to pass them. This Skill guides you through analyzing target code, planning test strategy across unit, integration, and E2E scopes, and generating framework-specific templates for Jest, PyTest, PHPUnit, Cypress, and other ecosystems.

Yes. This Skill supports framework-specific test templates and mocks across JavaScript/TypeScript (Jest), React Native, Python (PyTest), PHP (PHPUnit), Go, and other languages, applying consistent TDD principles regardless of your tech stack while respecting each framework's conventions.

Start by analyzing the existing codebase to identify untested paths, then write tests incrementally using TDD—failing tests first, implementation second. This Skill provides strategy guidance for unit, integration, and E2E scenarios, plus framework templates and fixtures to accelerate coverage gains across your tech stack.

Test strategy planning clarifies scope at each level: unit tests validate isolated functions, integration tests verify component interactions, and E2E tests confirm user workflows. This Skill guides scope selection and provides templates for each level across Jest, Cypress, Detox, PyTest, PHPUnit, and Go frameworks.

Framework knowledge helps but isn't required. This Skill generates framework-specific templates and mocks for Jest, PyTest, PHPUnit, Cypress, Detox, and Go, reducing setup friction. The TDD workflow—write failing test, implement code, refactor—remains consistent across ecosystems.

TDD works best when code is modular and testable; tightly coupled legacy code may require refactoring first to isolate units. This Skill supports analysis and strategy planning to identify which code sections yield to test-first development and which need architectural adjustment before testing begins.