test-driven-development

Test-driven development prevents bugs by enforcing a test-first approach where you write tests validating expected behavior before implementing production code. This upfront requirement validation reduces edge case failures.

The RED-GREEN-REFACTOR cycle is a structured test-driven development approach. You write a failing test (RED), implement code to pass it (GREEN), and refactor the code to improve quality while maintaining passing tests.

Yes, you can use pytest and unittest for test-driven development in Python. Both libraries provide the necessary test creation and execution capabilities required to validate behavior before coding actual function implementations.

The best way to start writing tests before coding is to write a test validating the specific behavior of your function. Ensure the test fails initially, then write the minimum production code needed to make it pass.

Yes, test-driven development works for fixing existing bugs. You write a test capturing the bug's incorrect behavior, verify it fails, and then fix the production code to ensure the test passes reliably.