test-driven-development

The Red-Green-Refactor cycle in test-driven development requires writing a failing test first, implementing minimal code to pass it, and then refactoring. This repeatable process reduces defects and improves maintainability across new features and bug fixes.

To start writing tests before production code for a new feature, write an initial failing test that defines the expected behavior. Then, implement the smallest amount of code required to make that failing test pass.

Apply test-driven development during new feature creation, bug fixes, and refactoring tasks. It enforces discipline by ensuring production code is never written before tests exist, keeping scope defined and execution cycles clear.

Yes, test-driven development includes guardrails for scope that define when exceptions apply. While it generally prevents production code from being written before tests exist, specific scenarios allow bypassing the strict Red-Green-Refactor cycle.

Unit testing is integral to the test-driven development approach. The cycle demands an initial failing unit test, a minimal implementation to pass it, and careful refactoring to ensure software engineering discipline and reduce defects.

Test-driven development prevents guessing by requiring an initial failing test that explicitly defines expected behavior. You only write the minimal production code necessary to pass that test, ensuring functionality is verified rather than assumed.