test-driven-development

Test-driven development is a workflow where you write a failing test first, implement the minimal code to pass it, then refactor. The red-green-refactor cycle drives this by ensuring every change is validated by tests before production code is introduced.

To write a failing test first, define the expected behavior before any production code exists. This test-driven development workflow ensures correct behavior is verified from the start, guiding you to implement only what is necessary to make the test pass.

Yes, test-driven development applies to refactors by ensuring every change is validated by tests. You write tests that capture current behavior, confirm they pass, refactor the code for clarity, and verify all tests still pass afterwards.

Test-first development requires understanding how to write unit tests that define expected behavior. The workflow guides you through a deterministic process with clear expectations for failing tests, minimal implementation, and refactoring only after all tests pass.

Test-driven development reduces regressions by making tests the primary contract for every feature, bugfix, and refactor. This deterministic process maintains quality across changes by validating behavior before production code is introduced.

The red-green-refactor workflow may not suit exploratory prototyping where behavior is undefined. It enforces a deterministic process requiring clear expectations for failing tests and minimal implementation, which works best when desired outcomes are well understood.