implement

To implement a feature using Test-Driven Development, write a failing test first, then create the minimal code required to pass it, and finally refactor the structure. This enforces the Red-Green-Refactor cycle for robust software progression from 0-1-N cases.

Separating structural and behavioral code changes during refactoring is achieved through Tidy First principles. This approach isolates internal code structure modifications from external feature behavior, ensuring maintainability without altering functional outcomes.

To fix bugs using API-level and problem-specific tests, write a test that reproduces the specific defect at the API boundary. Once the failing test confirms the bug, implement the minimal code resolution to make it pass.

Use the Red-Green-Refactor cycle for bug fixing when you need to ensure code quality and prevent regressions. By writing a failing test that captures the defect before applying code changes, you verify the exact problem and secure the fix against future breaks.

Feature implementation progression from 0-1-N cases starts by writing a test for the simplest zero-case, then the primary single-case, and incrementally adding edge-case tests. This structured progression ensures robust software development through incremental validation.