test-driven-development

Test-driven development (TDD) is a software development discipline that enforces writing tests before production code to drive correct implementation. It validates behavior through a strict Red-Green-Refactor cycle, requiring a failing test before any functional code is written.

To start writing tests first for a new feature, you begin by writing a failing test for the target behavior, then implement the minimal production code required to pass that test. This test-first approach sustains code quality and prevents misaligned implementations.

Yes, you can apply test-driven development to bug fixes and refactoring tasks where behavior matters. It provides guardrails to document rationale and validates fixes by requiring a failing test before altering code, ensuring early behavior verification.

Test-driven development requires a failing test before code to prevent regressions and verify behavior early. This strict Red-Green-Refactor cycle ensures you validate the test's effectiveness and drive correct implementation without skipping steps.

Enforcing a test-first approach requires strict adherence to the Red-Green-Refactor cycle, which may introduce initial development friction. It is limited to scenarios where behavior matters, requiring a failing test before code, which may not suit exploratory programming.