test-driven-development

Test-driven development is a workflow where you write a failing test, implement minimal code to pass it, and refactor for clarity while keeping tests green. This cycle defines desired behavior before implementation, reducing defects and guiding design.

To start writing tests first, write a failing pytest test specifying expected outcomes for the new feature. Next, implement the minimal production code required to pass that test, and then refactor the structure while ensuring tests remain green.

Yes, test-driven development applies to both feature development and bug fixes in Python projects. You start by writing a failing test that reproduces the bug or specifies the new behavior, followed by minimal implementation and subsequent refactoring.

You need a test framework like pytest to enforce a test-first workflow. The approach requires a clear test structure and a policy that every new feature starts with a failing test, followed by minimal implementation and subsequent refactoring.

Writing a failing test before production code provides early defect detection and validates desired behavior. This disciplined test-first workflow prevents late-stage fixes by ensuring implementation is guided by tests defining expected outcomes.

You should reconsider test-first development if your Python project lacks a test framework or clear test structure. The workflow requires a strict policy that every new feature starts with a failing test, followed by minimal implementation and refactoring.