running-tdd-cycle

To guide the TDD workflow in Python, start in the RED phase by writing a failing test, move to GREEN by implementing minimal production code to pass it, and then REFACTOR the code while keeping tests green.

The RED-GREEN-REFACTOR workflow drives design through tests by requiring a failing test first (RED), minimal implementation to pass the test (GREEN), and code refactoring without breaking tests (REFACTOR). It ensures tests drive feature implementation.

To start writing tests first for a new Python feature, begin in the RED phase by writing a failing test that defines the desired behavior, then let the TDD workflow guide you through the GREEN and REFACTOR phases for implementation.

You transition between RED, GREEN, and REFACTOR phases after explicitly completing the current step: write a failing test first, implement minimal code to turn it green, and then refactor the codebase while ensuring tests remain green.

Yes, you can use this TDD workflow for refactoring existing Python code by applying the REFACTOR phase, which guides you to improve the code structure while keeping the tests green to ensure functionality remains intact.