test-driven-development

The red-green-refactor cycle in test-driven development involves writing a failing test, implementing minimal code to pass it, then refactoring to improve design while keeping tests green. This enforces behavior verification before implementation.

To start writing unit tests before implementing features, identify the expected behavior and write a failing test for it. Then implement the minimal code required to pass that test before refactoring the design.

Yes, you can apply test-driven development to bug fixes and refactoring. Writing failing tests that reproduce bugs or target specific behavior keeps code clean and ensures correct behavior throughout the process.

To start test-first development, you need a test framework to run your tests. You write a failing test for intended behavior, implement minimal code to pass it, and then refactor.

Writing a failing test before implementing code clarifies requirements and ensures the test targets specific behavior. It prevents overengineering by encouraging a focused scope and verifies behavior before the implementation exists.