test-driven-development

Strict test-driven development in Rails requires enforcing a red-green-refactor workflow where no production code is written without a preceding failing test. This skill implements that iron law by systematically verifying code layer-by-layer.

The outside-in testing workflow starts with high-level feature specs and drops down to lower-level unit tests only when a failure demands it. This top-down strategy ensures every application layer is verified before completion.

Writing RSpec feature specs first requires starting with high-level user flow expectations, then dropping to request and model specs only as needed. This prevents technical debt and guarantees comprehensive coverage.

Yes, this TDD workflow applies to refactoring existing Rails code by enforcing systematic layer-by-layer verification. It eliminates the fragility of manual testing by ensuring high code quality and test coverage.

Outside-in TDD starts with feature specs to guide top-down design, dropping to lower-level unit tests only when the failure demands it. This ensures you build exactly what the feature requires without over-engineering.