test-driven-development

Test-driven development starts by writing a failing test that specifies the desired behavior, then writing minimal production code to make it pass, and finally refactoring while keeping tests green. This Red-Green-Refactor cycle ensures code meets requirements before implementation begins.

Red-Green-Refactor is the core TDD cycle: write a failing test (Red), implement the smallest code change to pass it (Green), then improve code quality without breaking tests (Refactor). This cycle repeats for each feature, bug fix, or behavior change.

Yes, TDD applies across feature development, bug fixes, refactoring, and behavior changes in any language. For bugs, write a failing test reproducing the issue, fix the minimal code to pass it, then refactor—ensuring the bug stays fixed.

TDD guides writing tests that specify exact behavior before implementation. Tests should cover both unit behavior and integration points, focusing on what the code must do rather than how it does it, ensuring correctness and maintainability.

TDD enforces correct behavior by requiring tests to pass before code ships, catching defects early. Writing tests first clarifies requirements and forces modular, testable design, reducing complexity and improving long-term maintainability.

Yes, TDD applies across languages. Start by writing a failing test for your function's expected behavior, write minimal code to pass it, then refactor for clarity—the same cycle works whether you're using Python, JavaScript, Java, or other languages.