test-driven-development

Test-driven development is a test-first workflow where you write a failing automated test, implement minimal code to pass it, then refactor while keeping tests green. This enforces red-green-refactor cycles to prevent regressions and eliminate unverified implementations.

To fix a bug with test-driven development, write a failing automated test reproducing the exact bug, execute it to confirm the expected failure, implement the minimal code to pass, and rerun the full test suite to detect regressions.

Start implementing new features with a test-first workflow by writing a single failing automated test, running it to confirm failure, writing the minimal code required to pass, and rerunning the full suite to catch any regressions.

Yes, test-driven development works for refactoring by keeping automated tests green. You run the full test suite after minimal code changes to ensure behavior remains reproducible and no regressions are introduced during the refactor.

Running the full test suite after passing a targeted unit test is required to detect regressions. Test-driven development enforces this verification step to ensure new code or bug fixes do not break existing reproducible behavior.

You should not use a strict test-first cycle when automated tests cannot reproduce the behavior or environment needed. It requires writing reproducible automated tests, making it unsuitable for tasks where automated verification is impossible.