tdd

Test-driven development validates software behavior by writing small, observable tests for public APIs first, failing fast, and implementing minimal code to pass each test. This iterative red-green-refactor cycle reduces risk during feature work and bug fixes.

The red-green-refactor cycle in test-first development involves writing a failing test, implementing the minimal code required to pass that test, and then refactoring while maintaining guardrails. This enforces rapid feedback and safe code improvements.

Write integration tests that focus on end-to-end behavior and public interfaces rather than internal implementation details. This approach supports safe refactoring by ensuring observable behaviors remain stable while internal code structures evolve.

Yes, test-driven development works for bug fixes in existing codebases by applying the test-first cycle. You write a failing test that captures the bug's incorrect behavior, then implement the minimal solution to make the test pass.

You should avoid testing implementation details in TDD when relying on public APIs and integration tests. Emphasizing testing through public interfaces prevents brittle tests and maintains refactoring discipline across iterative cycles.

The best way to start a TDD cycle for a new feature is to propose a small behavior, write a failing test that defines it, and then implement the minimal code necessary to pass the test before refactoring.