test-driven-development

To enforce red-green-refactor, write a failing test first, verify the failure reason, implement minimal code to pass, and refactor while keeping tests green. This test-driven development cycle prevents regressions and ensures behavior remains covered.

Test-driven development is a test-first workflow where you write failing tests before implementation. Apply it during new feature development, bug fixes, refactoring, and behavior changes to produce reliable, well-documented code and prevent hidden defects.

Start the TDD cycle by writing a failing test, running tests to confirm the expected failure, implementing the minimal code required to pass, and then refactoring the code while ensuring tests remain green throughout the process.

Avoid common test-driven development anti-patterns like testing mocks instead of behavior or adding test-only production methods. Use checklist checks to ensure tests drive implementation and validate actual behavior rather than implementation details.

Yes, apply test-driven development during refactoring to ensure behavior changes remain covered by tests. Verify tests fail for expected reasons before changes, require minimal implementation to pass, and keep tests green through the refactor.

In test-driven development, tests must fail initially because the implementation does not exist yet. Verify the failure is for the expected reason, then write minimal code to pass the test before refactoring.